When someone shows up to a party and drinks more than he/she can handle.
Not knowing their limits, they end up puking on your lawn or in your bathroom; possibly for a prolonged period of time.
Katy: Did you see Sam last night? He thought he could down 5 shots of whisky and then turned into a total yakmeister. He was puking all over the lawn!
Steph: What a loser.
Jagermeister to yakmeister.
Someone who drinks way to much,throws up multiples times, in conjecture with jagermeister. May even lock themselves out of their own room.
Stef: Sam could not handle her scandle and threw up five times last night.
Tony: She's the yakmeister !