This happened about a year ago when my band went to Disney World over Spring Break.
I was rooming with three other guys: Aaron, Jake, and Chris. There were two double beds, but we had also brought two air matresses. Aaron and I were lying on an air matress, the other two were on the beds. Aaron was asleep when an interesting topic came up. BOOBS.
Jake had brought it up talking about some girl in his math class's large chest. He talked about how he stares at them and how hard he gets. Well, I was getting hard talking about boobs. I'm a boob guy. Anyways, after about an hour of talking about certain girls' cleavage, I asked if Jake and Chris masturbated. They said yes after a pause and I said yes as well.
I was seriously hard by now after all this talk of breasts, so I said I need to relieve myself, and they said they need to too. I said why not at the same time. They agreed, and we all came thinking of that girl in Jake's math class and her gigantic boobs.