Do not confuse an insistent boner with Priapism. Yes, Priapism is a condition wherein an erection which will not go down even after ejaculation and requires medical attention.
Seriously, with Priapism, the trapped blood turns to sludge, Without a fresh supply of blood oxygen the tissues of the cock die. And a man should seek medical attention as soon as possible to have the blood drained, either by syringe
or by a port drain
An insistent boner will still wax and wane, like a normal erection, yet it keeps throbbing and twitching and can get painful after a while. Take the next session and use it for what is called Mindful Masturbation.
Really pay attention to the sensations in the cock, the way it will get real hard and then soften just a bit. This is the body circulating the blood in the Cavernosae; it draws a small amount out of the shaft, but not enough for a noticeable reduction in the hardness.
Then it fills up again.
The closer you get to spewing, the harder your cock will become.
When you reach the "point of no return," the Cremaster Muscles surrounding your nuts will contract, pulling your balls up, your cock will become extremely hard, and the first contraction grabs hold ejecting a shot of cum.
The orgasm subsides, the boner wilts, and the balls drop back down
Have a terrific weekend - Do some Mindful jacking off. Take your time, enjoy the trip. Because while the end result is wonderful beyond words,
The getting there is the real pleasure.
Today is my birthday... And I'll surely be spending it as described above.
Have a great weekend, folks.