When a person uses an enema to prepare for a anal session and does not eliminate all the water completely before the fun and accidentally shoots it out of their butt at an inopportune time.
"I was hooking up with this dude last night and when I gagged on his dick, I squirtled all over my feet."
Squirtle (noun): A tiny amount, usually water. Sometimes a cutePokemon characer.
Squirtling (verb): An action that may or may not involve a small spurt of water. In all cases, it's considered cute and adorable and not in any way demeaning to women.