Trample table tie down

Maybe I am blanking out, but in some videos I see the guys cock is tied down to the table while the lady tramples it. In Ambers newest video on C4S, she mentions using these tie downs, how is this done? I have a table and my gf complains that it’s hard to fully trample my cock and balls because they slide out from under her too easy, so I don’t want to tie it down to the table like in Ambers videos.

Any ideas?