Bump. This thread is a great read.
I think the IC muscle is automaticly engaged when a reverse kegel is initiated. As OP said just engaging the IC seems to get similar results as a full blown reverse kegel just more nuanced.
Its hard if not impossible to engage the IC and BC muscle at the same time. Kind of like Biceps-Triceps.
Wikipedia says it aids in creating an erection together with the BC.I think its a very fast twitch subconcious alternating movement that accomplishes that.
I have theory that maybe its possible ,through mastering BC and IC muscle, to create a willfull mechanical erection.
The BC pushes blood in while the IC restrains it from moving out. There is obviously a chemical reaction for an erection happening too, widening the smooth muscles, which enables them to fill(so probably a mechanical willfull erection is not possible on its own).
With a semierection and alternating BC and IC muscles Im able to fill my dick quiet some just by that willfull motion. This gets easier to do while beeing in a pump.
Wikipedia:
"
Ischiocavernosus compresses the
crus penis, and retards the return of the blood through the veins, and thus serves to maintain the organ erect."
What was described by spoonman84 about the balls beeing lifted up is right. I guess the cremaster is intertwined with the IC.
The way I engage the IC is a bit different then described here so I will add it:
The IC muscles is two legs that wrap along the inner CC's to unite left and right side of the base towards the top side.
I try to
move the two legs of the IC towards each other, forward and upward. I don't think Im really moving them together. Its more like a flex I guess but it helps to imagine it this way.
Doing this compresses the inner penis.
I used the pics from this thread to show the movement.
The red arrows explain to where I move the IC "legs". The right hand pic shows obviously only the left leg of the IC.
Doing this movement seems to also pull the anus a bit up/in and forward which makes sense looking at the anchor point. The whole movement as shown in the pic can also be done backwards which is most probably part of the Reverse kegel root lock described in minutemans thread.
My results are for sure harder erections. Like the reverse kegel it cancels out the BC muscle. Alternating both is fun and can create bigger erections. An intense BC kegel pushing blood in and then imemdiately switching to an IC kegel hold to hold the extra blood in.
Im not that well versed yet in ejaculation control but it seems to be able to stop the BC muscle twitches thus preventing too fast ejac but as others mentioned with reverse kegels it can if already gone further push one also over the top of ponr.
Another thing that can lead to much frustration is that localizing it at first might in some way tire it rather fast and one loses the control to find it.(try next day again)