actually it's HJ, not BJ.
Anyway the joke goes something like this.
A man walks into a sandwich bar and sees that the speciality of the
bar is that the girls behind the counter provide handjob for a
small fee.
As he walks up, he saw a swarm of drooling men oogling over the
girls and was promptly greeted by a sexy bombshell . He asks
"Do you do handjobs?". the girl looks at him seductively and purred
in a low sexy voice."Yes."
He moves in, returns her glance and said:
"Good. Go wash your hands, I want a sandwich"
