Keep stroking.
From Create Your Own Story
There is a shifts as you masturbates him and there is a tautness to his shoulders as his thighs tighten under your ministrations.
"If you keep doing that, I'm going to..."
The rest of the sentence dies out in a hoarse whisper as Jughead's toes curl.
"Dude, stop, I'm going to cum!"
You keep going and Jughead's toes curl in a fierce grip as ropes of semen shoot from his massive cock.