jack it up
Rapidly jacking your semi-hard dong after some foreplay so you can actually get it in someone, not because you want to cum, but because you hope it stays hard enough to finish the job.
I jack it up before bed so I can actually have sex instead of just cumming on the sheets.
He jacked it up so fast, I didn’t even get to finish my coffee.
She jacked it up before the party started, and now she’s ready to go.