Dear 100 Hour Board,
Is strict sex the only thing you can be kicked out of BYU for? What about hand jobs?
The exact behavior that could get you expelled from the university is up to the discretion of your bishop and the Honor Code Office. In theory any sexual behavior could have that consequence, depending on the circumstance.
If I could guess at why you're asking this question, you're either considering doing something like that, you already have done it and feel nervous talking to others/your bishop about it, or it's a random question that came up and you don't know the answer. To the first possibility: even if you completely disregarded the law of chastity and anything to do with God, there is a chance that people will find out and you could face problems at BYU. Like Luciana said, that does depend on the Honor Code Office and your standing at the university (for instance, some sport players at BYU have gotten away with breaking the Honor Code, while most students are punished or expelled for such actions). If this is something you're considering doing, I would say to wait until after you leave BYU. Again, completely ignoring the spiritual side of this, I don't think that's worth possibly jeopardizing a greatly subsidized education.
If it's something that has already happened, I want to assure you that there are great bishops who separate your spiritual life and BYU. I have friends who have talked to their bishop about doing similar things, and the bishop's number one priority is to help them and won't involve BYU unless absolutely necessary. I can't speak for all bishops, but if you ask around your ward you can get a sense of what your bishop's like. And if you aren't sure but want to talk to someone/a bishop, you can always email me or I can send you my bishop's info, because he's possibly the greatest YSA bishop in Provo.
And if this was just a random question, by this point you're like, "What on earth is guppy doing? I just had a random question, and now she's offering to send me her bishop's information? She's worse than the Honor Code Office!" Well, Mallory, I'm sorry you had to read my whole answer, because there's really nothing more to add to Luciana's answer. It really just depends on your bishop and the Honor Code Office, and that applies to basically all sexual behavior.
-guppy of doom