Does this work:

ok

noooo it d oes not! is a nice pic to check out
HERE:
https://i.imgur.com/qGuO79M.jpg
EVERYONE TRYING TO UNDERSTAND IC check this pic out.
The arrows show the direction of the IC clenching/contracting.
btw. the "back" part of the IC where it spreads more can be activated and then you can do a BC muscle "kegel". That BC muscle kegel overrides the IC front part.
The exercise is:
Done at all erection levels but best noticed/effect with semi or erection.
Clench the IC muscles, the whole thing as seen in the pictures.
Hold it, increase pressure really hard(RK same time can help too).
Then do a fast BC muscle clench, to push blood up the CS into the glans, WHILE focusing on the IC hold at the back part where it spreads into the diagonal part(as seen on picture). Try to keep the hold there going while the BC fast clenches
The fast BC clench should override the IC hold in the front part but it has less antagonist influence on the back part.
Once the BC clench is done immediately switch to the full IC hold back. That stops the the blood rushed in via the BC to remain.
If you keep doing that you will be able to increase the blood inside the penis without a tool or hands ..just with your muscles.
I basically balloon my penis. Very fun with a semi erection. But a seemingly 100% erection can also be inflated with this technique.