>>330652476
With my hand usually. The towel method does work but it's not perfect and it can be annoying if the ona doesn't stay in position. You have to tie something around it in at least two places, one to hold the onahole and another even tighter behind the onahole to stop the ona being accidentally pushed in. If the lube starts to dry or the towel shifts about too much the onahole might get pulled out along with you, so you have to be careful about that too.

If you've got the cash to spend, one of those plush torsos with onahole inserts would probably feel great. They were popular in /jp/'s onahole threads a number of years back so check there if you're interested.