A blonde, brunette, and redhead all get into an elevator. They soon realize that a substance on the wall looks like cum. The brunette leans in, takes a close look, and says "it looks like cum." The redhead next leans in, takes a big sniff, and says "it smells like cum." The blonde immediately sticks her finger in it, puts her her finger in her mouth to taste it, and says "not a guy in this building."