• Do it in the shower. It won't clog unless you're squirting a quart at a time, and if that's the case, you're going to get wealthy in the porn industry.

• Use toilet paper. Is she monitoring how many squares it takes to wipe your ass?

• Buy your own tissues. Or steal fast food napkins, or something.

• Get a job, and move out.

OR:

Grow up and stop playing your mom's sick, twisted game. Take as many tissues as you want, and TELL her she is a sick fuck who gets no explanation, and to stop thinking about her son's genitals. Your genitals belong to you, and she has no say in what you do with them. And if she won't stop, start telling EVERYONE around her about her perverse proclivities, her friends, family, co-workers, neighbors, people at church, etc. Let everyone know what a complete weirdo she is.