I'm a woman, personally, and I don't squirt but from experience (talking to guys, things on the Internet, etc.), men seem to really like squirting. Obviously, this isn't all men but nothing is ever relevant to EVERYONE. And you needn't resort to only shower sex! Get a Liberator Shag Throe
or one of the similar products. If you don't have the money or points for that, try getting an old blanket you don't want and folding it over a few times and having it lay underneath of you. That could possibly work.
EDIT: I'm not sure how much they are but I know they sell pads for kids who wet the bed so there's an option, as well.