I hooked up with the guy that my friend has been texting and has a crush on. He asked her to formal the next day and I'm going to be at the same formal, so I'm worried that she might find out. Should I tell her what happened or just let it go?

Well, if you value your friendship then yes, you have to tell her. The only alternative is if you can get in contact with him and ask him not to say anything... but then you have to know that you can trust him.

It's a complicated situation but one that we have probably all found ourselves in at one time or another.

Why did you initially decide to hook up with him? I'm only curious because generally, if a friend likes someone, he becomes off limits to us. So I am wondering if you too have feelings for him?

He does sound like a bit of a player though, hooking up with you and then asking her out the following day... I take it he knows that the two of you are friends?

I think you do need to tell your friend, although you do stand the chance of her not speaking to you for a while so be aware of that. However, I think it would be much better coming from you than from him, and to be honest, I think she needs to be aware of what kind of guy he is.

Let me know how you get on, good luck.