Just a quick variation if you will, to this, that I forgot about.
Using an already existing exercise, no ordinary one
but the SSJ you combine that with the boa but focus more on the glans, and using one hand as you push against the head, angle it downwards to really get a full expansion ... kegel to ensure its fully engorged, and you can use the index finger to sorta jelq the glans gently from the tip to the coronal ridge a few times if you wanted to work on your 'ridge'.
This is what I used to do when combining SSJ with the Boa - SSJ Boas - with emphasize on the glans and coronal ridge.
I would hold it there for 30 seconds or so, so the head was fully expanded after the SSJ, and its angled downwards at this point, sometimes looking quite extreme, you can really bend the glans, it is anchored to the shaft by a ligament so dont panic about snapping it off
you get amazing definition in the coronal ridge, the depth of mine now is allot more then it ever was.
Questions, please ask.