At the moment the guy realizes she is finally going to let him come, he usually immediately shoots an initial wad with the force of a rifle. Then wave after wave of ecstasy engulf his body as his balls squeeze gobs and gobs of jism into her willing orifice. Once you're convinced you've swallowed his entire load, gently let it go. After ejaculation, the penis is very, very sensitive and further stimulation is counter-productive. Let the guy be a beached whale for a minute or two.
Ejaculation saps a guy's strength temporarily, especially if it's a really good one.
Once he's recovered a little, you can kiss him on the lips, or just nuzzle him. Whisper in his ear about how good he tasted.