How can i sign in using my friend's gmail account

[Sayan sharma]

My friend recently opened a new base in clash of clans and he asked me to play with that account.....
The problem is that I don't know how to get his gmail account on my phone.....
Please solve my problem

 

[hang-the-9]

http://android.stackexchange.com/questions/4955/how-to-change-the-account-for-android-market