Had another love making session with wife yesterday very similar in progression to my previous post " Making Love the the Vice".
When we got to the intercourse stage I tried something different since discovering the Progasm. I was matching my kegels with my pumping into her. It was quite pleasurable but not as auto as the Progasm. I think the thinner neck on the Progasm is the key to the autof**k. So I am thinking my next lovemaking session will include the Progasm for some variety ! Cheers !
Source: https://www.aneros.com/blogs/vice-lovemaking-session/