diff --git a/lib/application.js b/lib/application.js
index 9aec792..84107cb 100644
--- a/lib/application.js
+++ b/lib/application.js
@@ -14,7 +14,6 @@ const isJSON = require('koa-is-json');
 const context = require('./context');
 const request = require('./request');
 const statuses = require('statuses');
-const Cookies = require('cookies');
 const Emitter = require('events');
 const util = require('util');
 const Stream = require('stream');
@@ -169,11 +168,6 @@ module.exports = class Application extends Emitter {
     request.response = response;
     response.request = request;
     context.originalUrl = request.originalUrl = req.url;
-    context.cookies = new Cookies(req, res, {
-      keys: this.keys,
-      secure: request.secure
-    });
-    request.ip = request.ips[0] || req.socket.remoteAddress || '';
     context.state = {};
     return context;
   }
diff --git a/lib/context.js b/lib/context.js
index 88ec1ae..1b92f01 100644
--- a/lib/context.js
+++ b/lib/context.js
@@ -10,6 +10,9 @@ const createError = require('http-errors');
 const httpAssert = require('http-assert');
 const delegate = require('delegates');
 const statuses = require('statuses');
+const Cookies = require('cookies');
+
+const COOKIES = Symbol('context#cookies');
 
 /**
  * Context prototype.
@@ -151,6 +154,20 @@ const proto = module.exports = {
     this.status = err.status;
     this.length = Buffer.byteLength(msg);
     this.res.end(msg);
+  },
+
+  get cookies() {
+    if (!this[COOKIES]) {
+      this[COOKIES] = new Cookies(this.req, this.res, {
+        keys: this.app.keys,
+        secure: this.request.secure
+      });
+    }
+    return this[COOKIES];
+  },
+
+  set cookies(_cookies) {
+    this[COOKIES] = _cookies;
   }
 };
 
diff --git a/lib/request.js b/lib/request.js
index 9ef7c49..9f56410 100644
--- a/lib/request.js
+++ b/lib/request.js
@@ -17,6 +17,8 @@ const fresh = require('fresh');
 const only = require('only');
 const util = require('util');
 
+const IP = Symbol('context#ip');
+
 /**
  * Prototype.
  */
@@ -439,6 +441,26 @@ module.exports = {
       : [];
   },
 
+  /**
+   * Return request's remote address
+   * When `app.proxy` is `true`, parse
+   * the "X-Forwarded-For" ip address list and return the first one
+   *
+   * @return {String}
+   * @api public
+   */
+
+  get ip() {
+    if (!this[IP]) {
+      this[IP] = this.ips[0] || this.socket.remoteAddress || '';
+    }
+    return this[IP];
+  },
+
+  set ip(_ip) {
+    this[IP] = _ip;
+  },
+
   /**
    * Return subdomains as an array.
    *
diff --git a/test/context/cookies.js b/test/context/cookies.js
index c6daf53..e12df80 100644
--- a/test/context/cookies.js
+++ b/test/context/cookies.js
@@ -5,51 +5,13 @@ const assert = require('assert');
 const request = require('supertest');
 const Koa = require('../..');
 
-describe('ctx.cookies.set()', () => {
-  it('should set an unsigned cookie', async () => {
-    const app = new Koa();
-
-    app.use((ctx, next) => {
-      ctx.cookies.set('name', 'jon');
-      ctx.status = 204;
-    });
-
-    const server = app.listen();
-
-    const res = await request(server)
-      .get('/')
-      .expect(204);
-
-    const cookie = res.headers['set-cookie'].some(cookie => /^name=/.test(cookie));
-    assert.equal(cookie, true);
-  });
-
-  describe('with .signed', () => {
-    describe('when no .keys are set', () => {
-      it('should error', () => {
-        const app = new Koa();
-
-        app.use((ctx, next) => {
-          try {
-            ctx.cookies.set('foo', 'bar', { signed: true });
-          } catch (err) {
-            ctx.body = err.message;
-          }
-        });
-
-        return request(app.callback())
-          .get('/')
-          .expect('.keys required for signed cookies');
-      });
-    });
-
-    it('should send a signed cookie', async () => {
+describe('ctx.cookies', () => {
+  describe('ctx.cookies.set()', () => {
+    it('should set an unsigned cookie', async () => {
       const app = new Koa();
 
-      app.keys = ['a', 'b'];
-
       app.use((ctx, next) => {
-        ctx.cookies.set('name', 'jon', { signed: true });
+        ctx.cookies.set('name', 'jon');
         ctx.status = 204;
       });
 
@@ -59,36 +21,99 @@ describe('ctx.cookies.set()', () => {
         .get('/')
         .expect(204);
 
-      const cookies = res.headers['set-cookie'];
+      const cookie = res.headers['set-cookie'].some(cookie => /^name=/.test(cookie));
+      assert.equal(cookie, true);
+    });
 
-      assert.equal(cookies.some(cookie => /^name=/.test(cookie)), true);
-      assert.equal(cookies.some(cookie => /(,|^)name\.sig=/.test(cookie)), true);
+    describe('with .signed', () => {
+      describe('when no .keys are set', () => {
+        it('should error', () => {
+          const app = new Koa();
+
+          app.use((ctx, next) => {
+            try {
+              ctx.cookies.set('foo', 'bar', { signed: true });
+            } catch (err) {
+              ctx.body = err.message;
+            }
+          });
+
+          return request(app.callback())
+            .get('/')
+            .expect('.keys required for signed cookies');
+        });
+      });
+
+      it('should send a signed cookie', async () => {
+        const app = new Koa();
+
+        app.keys = ['a', 'b'];
+
+        app.use((ctx, next) => {
+          ctx.cookies.set('name', 'jon', { signed: true });
+          ctx.status = 204;
+        });
+
+        const server = app.listen();
+
+        const res = await request(server)
+          .get('/')
+          .expect(204);
+
+        const cookies = res.headers['set-cookie'];
+
+        assert.equal(cookies.some(cookie => /^name=/.test(cookie)), true);
+        assert.equal(cookies.some(cookie => /(,|^)name\.sig=/.test(cookie)), true);
+      });
+    });
+
+    describe('with secure', () => {
+      it('should get secure from request', async () => {
+        const app = new Koa();
+
+        app.proxy = true;
+        app.keys = ['a', 'b'];
+
+        app.use(ctx => {
+          ctx.cookies.set('name', 'jon', { signed: true });
+          ctx.status = 204;
+        });
+
+        const server = app.listen();
+
+        const res = await request(server)
+          .get('/')
+          .set('x-forwarded-proto', 'https') // mock secure
+          .expect(204);
+
+        const cookies = res.headers['set-cookie'];
+        assert.equal(cookies.some(cookie => /^name=/.test(cookie)), true);
+        assert.equal(cookies.some(cookie => /(,|^)name\.sig=/.test(cookie)), true);
+        assert.equal(cookies.every(cookie => /secure/.test(cookie)), true);
+      });
     });
   });
 
-  describe('with secure', () => {
-    it('should get secure from request', async () => {
+  describe('ctx.cookies=', () => {
+    it('should override cookie work', async () => {
       const app = new Koa();
 
-      app.proxy = true;
-      app.keys = ['a', 'b'];
-
-      app.use(ctx => {
-        ctx.cookies.set('name', 'jon', { signed: true });
+      app.use((ctx, next) => {
+        ctx.cookies = {
+          set(key, value){
+            ctx.set(key, value);
+          }
+        };
+        ctx.cookies.set('name', 'jon');
         ctx.status = 204;
       });
 
       const server = app.listen();
 
-      const res = await request(server)
+      await request(server)
         .get('/')
-        .set('x-forwarded-proto', 'https') // mock secure
+        .expect('name', 'jon')
         .expect(204);
-
-      const cookies = res.headers['set-cookie'];
-      assert.equal(cookies.some(cookie => /^name=/.test(cookie)), true);
-      assert.equal(cookies.some(cookie => /(,|^)name\.sig=/.test(cookie)), true);
-      assert.equal(cookies.every(cookie => /secure/.test(cookie)), true);
     });
   });
 });
diff --git a/test/request/ip.js b/test/request/ip.js
index 8c8cb09..3375f70 100644
--- a/test/request/ip.js
+++ b/test/request/ip.js
@@ -39,11 +39,21 @@ describe('req.ip', () => {
     });
   });
 
-  it('should be cached', () => {
+  it('should be lazy inited and cached', () => {
     const req = { socket: new Stream.Duplex() };
     req.socket.remoteAddress = '127.0.0.2';
     const request = Request(req);
+    assert.equal(request.ip, '127.0.0.2');
     req.socket.remoteAddress = '127.0.0.1';
     assert.equal(request.ip, '127.0.0.2');
   });
+
+  it('should reset ip work', () => {
+    const req = { socket: new Stream.Duplex() };
+    req.socket.remoteAddress = '127.0.0.2';
+    const request = Request(req);
+    assert.equal(request.ip, '127.0.0.2');
+    request.ip = '127.0.0.1';
+    assert.equal(request.ip, '127.0.0.1');
+  });
 });