Giving a girl a mouthful of sperm. Since it has a consistency similar to mayo, combined with a girls mouth it immulates what having a mayo sandwich in her mouth would look like.
When 3 lesbians get together and scissor and at least one of them has an STD/STI or at least a yeast infection Hence the "Cheese"
You hear about Carly, Alex, and Jenny? Those three had a Cheese and Mayo Sandwich. One of em has herpes and one of em has a yeast infection and Alix is a squirter