1. The act of giving fellatio while simultaneous skiing up a mountain in the moonlight.
Jimmy was devastated when his friends discovered that he was actually a Kathrin in a sex club on weekends.
Florian: How was your blind date last night?
Guunter: Ach du lieber himmel!! Helga was amazing!
Florian: You mean the chick with the one eye?
Guunter: DUDE! She gave me a Kathrin last night! AND I got to cum in her eye!