First, have you considered just saying “masturbation?” It’s a fine and good word to say; plus, it’s gender-free! But if you really can’t do it — or if you’re some kind of slang aficionado — you’ll be thrilled to know that there are dozens of unusual euphemisms for masturbation at your disposal.
We’ve compiled a selection of 50 for you here, all from the deep tunnels of our blessed internet. Some of these images are specific to female masturbation, and some are specific to male masturbation. (We need more terms that aren’t just for men, to be honest.) Some are not specific at all. And some are so deeply confusing that we simply do not know to which body parts they are referring. But maybe you do. In that case, can you let us know?