Glow-In-The-Dark Radioactive Element Soaps
These are the glow-in-the-dark radioactive element soaps made and sold by scientific supply company United Nuclear. You can buy them separately for $7.50 apiece or get all three for $19. You should buy one and scrub your privates with it real good then ask your girlfriend if they're glowing. Even if they're not, it's still pretty cool she paid attention to your penis for a second.
Thanks to carrie, who, for two tips in two days, can come up to my desk and choose any prize out of the red bucket. "But it's empty." Better luck next time.