I’m not very experienced nor well-informed with PE, but still, I have a point to add.
To get my EQ better, I’ve been doing 75% erect jelq, some kegeled, with a kind of an inverted OK grip. I would place the, ehm, dip between the thumb and index fingers not on top of the penis, but, rather, on the side - left side using right hand and right side with left hand. The distal (tip) phalanxes of index and middle fingers press on CS very firmly that way. I couldn’t move the hand all the way to head due to extreme pressure in the head and CS - borderline painful. I didn’t intend that technique to expand head specially, only to increase EQ.
I have definitely noticed some enlargement of head, higher firmness of head, some more CS protrusion, and - my key point - the visible CS had became longer. I always had quite prominent CS, but at just below midshaft, it would recess to nothing. Now, it recesses a little closer to the head.
So, I have a hypothesis: Before starting head-isolated exercises, one should try to make his CS as close to the head as possible. I don’t very well know how, but have an idea:
Wet jelq with the grip described above. You should have very strong palms and fingers, work them out. Erection level should be such that it would be possible to bend the penis without extreme force, but there would be a definite resistance - about 50%, I think. Kegel blood before each move. Start from the base itself, with a very firm grip, really very firm. After an inch or so, pressure in tunica should make it firm, pressure in CS should provide a massive feel of expansion. Head should get roch hard. At that moment, increase pressure on CS and try to move further. You shouldn’t be able to move any further, actually, yuo should only be able to stretch. Hold that for 10-15 seconds.
It should be quite extreme - i do New City Jelq that way, only at no more than 25% erection, and expansion of tunica is massive. Not much CS expansion though, and massive fluid buildup. At 50%, it’s a different thing, tunica is firm enough to allow CS compression between itself and the fingers.
And then, after getting your CS to nearly your head (don’t know how near, though..), you can start common head exercises, like Sadsak Head etc.