A young guy drops off his girlfriend at her home after being out together on a date. When they reach the front door he leans up against the house with one hand and says to her, "How about a blowjob?"  
"What! Are you crazy!"  
"Don't worry, it will be quick," he ensures his girlfriend.  
"No! Someone might see us..."  
"It's just a small blowjob," he insists, "and I know you will like it."  
"No! I said no!"  
"Baby... don't be like that."  
Suddenly, the girl's younger sister shows up at the door in her nightgown, with her hair a mess, and rubbing her eyes. She looks at them and smirks, "Dad says either you blow him, I blow him, or he'll come downstairs and blow the guy himself... but for God's sake tell your boyfriend to take his hand off the intercom."