Let's keep this brief.

When Peter Parker is sticking to walls and ceilings, he doesn't like to get a wedgie. That's why he wears these Ultimate Spider-Man boxer briefs.

What? You thought he went commando? These are so comfortable you’ll wonder if they were made of silk from a spider’s spinnerets. On the left leg is a big red spider which is a signal to all the other spiders crawling around your room that you have already been bitten.