Click the gear in the upper right hand corner of gmail and go down to settings.
Go to the account tab and hit add another email address you own.
Put in your name and tufts email address, and uncheck treat as an alias.
Hit send through tufts.edu SMTP servers, and put in the following information:
SMTP Server: exchange.tufts.eduÂ
Port: 587
Username/ Password: your tufts credentials
You want to make this a secured connection using TLS.