wanke-danke-thon
This is an extended masturbation session of gratitude, formed by combining the words "wank" + the German word "danke" for thank you + "thon" from marathon.
Mom: Alright son, I fixed you a great supper. How are you going to thank me?
Son: Mom, I am going to do a wanke-danke-thon in your honor tonight.
Mom: Oh I am flattered!
Son: Mom, I am going to do a wanke-danke-thon in your honor tonight.
Mom: Oh I am flattered!