Bobby used to find slutty girls upsetting. He had been thirteen, and adults never understood that there was a difference between ninth grade and twelfth grade. They just crammed everyone together in the same school, and pretended not to see the younger students meltdown. It's something he likes about Professor Xavier's school; the teachers understand every student is capable of meltdown. They watch for it.
Regardless of what the adults (teachers, parents, school boards alike) thought, there was a difference between a thirteen year old boy just learning to jerk off, and a eighteen year old girl walking in a skirt high enough to see her ass. The difference was vast enough to form an endless chasm, and Bobby often felt like he was falling down it. Every moment spent in the halls was a nightmare, a struggle to not frost the metal lockers. Rachel Labonte's V-necked shirts finally prompted him to look for a place mutants could go, a place where he wouldn't have to frantically try to blow-dry the sheets so they would be warm and dry before the maid came by to wash them in the morning.
None of the girls at Xavier's School For Gifted Youngsters put themselves out, like some sort of cruel buffet that Bobby can't eat, but can still smell and see. It's probably because no one is sure yet how to control their powers during the heightened emotions of sex. Sex is good, but not killing someone -or yourself- is better. Rumour has it Jean Grey can tell when it's going to become an issue, and has a lecture prepared. Abstaining avoids that. Sex is good, but not dying of embarrassment is better.
Bobby used to find slutty girls upsetting, and now he's dating the definition of prude, personified. There's not a chance he and Rogue will ever hook up, not when even simple kissing is potentially deadly. It's refreshingly safe. He does wonder what it would be like to have someone cause your orgasm, but will never ask.
His roommate doesn't understand why he'd choose to abstain. That's because John doesn't understand anything. He doesn't understand why listening is more important than acting, why holding back is more important than bursting forward. He doesn't understand what it's like to be scared to orgasm because you don't think you have any control. John isn't scared, because all of his power is in a Bic.
John keeps on tempting him. It's not fair. It's like freshman year all over again. John's a slut, but only for Bobby's eyes. The minute he enters their bedroom, he strips down. It's impossible to concentrate on anything when there's a skinny bombshell walking around in badly fitted Y-fronts. They're either too tight, cutting off circulation, but making his ass look round and spankable, or they're too loose, and the worn elastic makes them nearly fall off his hips. John's underwear is incredibly inappropriate, but how do you complain about that to a teacher?
And God knows he can't tell John. John takes any discomfort on Bobby's part as a clue on how to bother him more. And rightly so. Bobby knows one day he'll crack. If John came on to him, he wouldn't stop him. He doesn't think he could stop John, doesn't think he could stop himself. The same goes for Rogue, or Storm, or any person in the school. Bobby is a petrified satyrist; he'll do anything offered to him, but cannot offer.
It's difficult to live with this difference, not wanting to hurt anyone, but desperately needing to be with someone. He plasters on a shiny front, and tries not to notice when John bends over to pick up his socks. The Y-fronts are tight today.