Fucking My Roommates Girlfriend

So I'm just hanging out watching vids on my phone, when my roommates girlfriend comes busting in to use my mirror! She wanted to use it to take pictures in her Lingerie to send to my roommate while he's away on a trip for a month. As if I'm going to tell her to NOT come into my room half naked anymore? Next thing I know, she's offering me to touch her tits, my pants are coming down, and I guess I owe my roommate an apology