"Nudist Colony" joke

Bob joins a very exclusive nudist colony. On his first day he takes off his clothes and starts wandering around. A gorgeous petite blonde walks by him and the man immediately gets an erection. The woman notices his erection, comes over to him grinning sweetly and says: "Sir, did you call for me?"
Bob replies "No, what do you mean?"
She says: "You must be new here; let me explain. It's a rule here that if I give you an erection, it implies you called for me."
Smiling, she then leads him to the side of a pool, lays down on a towel, eagerly pulls him to her and happily lets him have his way with her.
Bob continues exploring the facilities. He enters a sauna, sits down, and farts. Within a few moments a huge, horribly corpulent, hairy man with a firm erection lumbers out of the steam towards him. The Huge Man says: "Sir, did you call for me?"
Bob replies "No, what do you mean?"
"You must be new here, it is a rule that when you fart, it implies you called for me."
The huge man then easily spins Bob around, bends him over the bench and sodomizes him.
Bob rushes back to the colony office. He is greeted by the smiling naked receptionist: "May I help you?".
Bob says: "Here is your card and key back. You can keep the $500 joining fee."
"But Sir, you've only been here a couple of hours; you only saw a small fraction of our facilities..."
Bob replies: "Listen lady, I am 58 years old, I get a hard-on about once a month, but I fart 15 times a day. No thanks!"