system
A chat on subreddit /r/me_irl
human
Lubrication also helps a lot. If the man in question isn’t producing enough already on his own, store-bought is fine. Just like a woman needs lubrication to enjoy penetration, a guy kinda needs it for penile stimulation to avoid friction discomfort (and helping to avoid the need for a death-grip, which can leave the penis bruised and achey).
gpt
Shit I've always been a dry jerk kind of guy and my hand just physically starts dying some times because of the death grip. 

Like right between the thumb and the index finger where all that fatty skin is, ouch. It's just a really tense pinch. 
If it gets real bad even my knuckles ache and then the thumb joint just hurts so much I gotta stop. 

Didn't used to be like that, and it shouldn't be an aging thing since I'm only just in a few days turning 20. I do game a lot though so maybe it's a sign of early arthritis. Hope not though.