Give them a baby

A year ago, your gooner friend finally managed to get a girlfriend before you, so he was bragging about it for a while. (What an idiot.)

However, a few days ago, he called you to tell you he discovered he's infertile. He had been trying to give Sophie a child but always failed, so he asked you to have private sessions with his girlfriend, since he enjoys watching more than doing it, and since you are his only friend, he only trusts you.

Somehow, Sophie reluctantly agreed, simply because she loves him. (And you still don't know why.)

Bro power!