I don't usually get this naked right away when I bring a fella up to my flat.
Here's how it usually goes: I bring him up, and then I have him sit down in a chair in front of my bed.
I pull down his pants and underpants and get down on my knees in front of him.
I then proceed to wank him off, slow at first, but then I start doing it quite fast, pulling his foreskin back with the thumb and index finger with one hand and rubbing the sensitive head with the other.
If he loses his erection, my handjob can easily become a blowjob. I don't mind, really. It's all about him at this moment.