Conversations between these two would probably be hilarious:
Friend: Penny for your thoughts?
Yuuki: I wanna do my mother.
Friend: Haha, you're so funny.
Yuuki: You know what's funny? Japanese marriage laws. Why is incest illegal anyway?
Friend: We're still doing this gag, huh? Don't you think it's gotten a bit old?
Yuuki: You know what doesn't get old? My mother. Ass like a twenty-eight year old.
Friend: Oddly specific. You really love the whole mamacon bit, huh?
Yuuki: She doesn't let me bite her. Something about the marks being suspicious.
Friend: Ooookay, time to change the topic. What'd you have for breakfast this morning?
Yuuki: My mother.
Friend: .....