Great question.
When I wank, I’d say I usually slow down quite a bit. Sometimes down to one or two strokes per spurt. Sometimes I keep the same quick rhythm and stroke really hard straight through until I’m done shooting. Both feel good
When I’m getting a blowjob I just let her do her thing, unless I’m pushing her head down and controlling the pace, in which case I generally speed up as I cum.
While fucking (and controlling the pace), I generally slow down and thrust really hard in time with my spurts if I’m cumming inside her.
If I’m getting a handjob, it’s all down to her. I’ve had chicks who speed up as I cum, some who keep the same pace and some who slow right down. And the there are the really evil ones who make you think you’re going to have a great orgasm but just let go as you reach the point of return and ruin your orgasm