If they’ve still got a prostate, anus, nipples, neck, or mouth, you might be able to make it work with enough foreplay. I made a woman come from licking her nipples once. Definitely hard-mode though.

1. Put on glasses
2. Lean forward until glasses hang from your ears
3. Get tense/angry, notice glasses move toward your face
4. Relax, notice glasses move away from your face
5. Repeat 3-4 until you isolate the muscle