1) He is trying to brag that he's banging a 20 year old, but she's not even attractive. She's ugly, has a terrible tattoo and makes you feel uncomfortable looking at her. Her youth doesn't really add to her appearance in any way because she's still just ugly. There's women with an extra 30 years on the clock I consider way more attractive.
Not that I want to go into the grotesque specifics, but does Boogie even bang her? He's so fat and on psych meds, the only thing that gets him off at this point is probably food and emotional manipulation.
I generally imagine how a boogie sexual encounter goes is that the girl is sitting on a couch messing with her phone, and Boogie will waddle in, clearly in the mood, and sit down next to her.
She knows what comes next, so with a quiet sigh she sets her phone down and readies herself.
At this point Boogie begins telling her all about how he was abused and raped or w/e as a little kid. It was a tough childhood you see, they were really poor, and he thought about ending it all many times, but...[insert another 15 minutes of boogie-isms].
It's a struggle to keep the bile down (as it would be for anyone), but this is what she gets paid for, so she "aw"s and "poor baby"s where she should.
Eventually at the climax of his story she goes "I'm sorry that happened, you're such a strong guy and we all love you and are glad you're still here!". This causes him to immediately finish, and he hefts himself up with a grunt and heads back to the kitchen to refuel since 17 minutes is a long time to go without a meal so he's getting very peckish.
She goes back to her phone, praying that he'll be satisfied for the day.