Is a person who loves getting on the lash, playing sport, having sex, and just anything very manly. It's the same thing as being a "Lad" but its the name for a person who is the ultimate "Lad". Its a term discovered by uni students around Britain.
Person 1: Hey, man, I got that sweet blue belt!
Person 2: nice! When's the next step 1: I dunno, soon-ish
Person 3: You have contracted Lariat's disease