This question is very frequently asked by those people who have multiple G mail accounts, that how can we login two G mail accounts at the same time. The answer is yes we can login two accounts simultaneously. G mail has given this option and the process is given below.First login to your secondary G mail account and go to the Settings --> Accounts and Imports and there you will see the option of "grant access to your account". You can see in below image.
Click it, where it says "add another account" and enter your primary G mail address which you want to share with this address. After you have done this, a notification e-mail will go to your primary e-mail account and you will have to accept that request.
Now, go to your primary G mail account and there you will see a confirmation email, accept it and now you have done. After granting the request log-out and login again and go to the upper right corner from where you sign-out your account, there you will see an option "switch account" click on it and access you another account.
