Wrong use of the word 'Fuck'

Rocky has broken his leg and his buddy Bob comes over to see him.

Bob: How are youy doing?

Rocky: Fine. Hey, do me a favor. Go upstairs & get me my slippers. My feet are freezing!

Bob goes upstairs and sees Rocky's hot twin sisters lying on the bed.

Bob: Your brother sent me up to have sex with you girls.

Twins: Oh Really??? Prove it!

Bob (Shouting): Hey Rocky, both of them?

Rocky (Shouting back): Of course! What's the point of fucking one?