Late one night this guy is walking his girlfriend home. When they get to her house he leans against the side of the door, trying to look all sexy and says "Give me a blow job."
:No" she said, "My parents are home."
"That's OK" he said "They're asleep. It's late."
"But I can't It's my house" and it went on for a while, with him leaning against the side of the door begging and she's saying no.
Suddenly a window opens and the girlfriends sister put her head out.
"Dad says, give him a blow job. If you won't do it, I'll do it. If necessary Mom will come and do it. But whatever, get his hand off the intercom."