Here’s something I’ve been toying with recently: during a good edging session, instead of exclusively clamping, press the first two fingers of your hand firmly over you CS quite far down near the base of the penis, with your thumb on the topside at base. Whilst in this position, gently jerk the grip up and down a half inch or so, with more emphasis on the upward motion.
Gradually the CS will fill with blood to an almost clamp-like pressure, but on a totally manual level. I’ve been incorporating that with some ballooning techniques and apart from good expansion, it feels fantastic.
This technique is a step down from clamping but worth trying all the same. Maybe a good preparation for those looking to get into clamping too.