"Thrussy Bussy" is a complex word that can be used in many
circumstances.
The Breakdown:
Thrust is a word often used to describe a powerful motion in a particular direction. In that word specifically it is used to compose the
first word (Thrussy) and is being used in a sexual conation.
The "Bussy" half is more
complicated. "Bussy" could either mean a bus, man bussy or just mean busting in general.
If I were to narrow it down to 1 definition it would be:
Verb: The act of thrusting the proceeding to bust
Adj: A way to describe an object that is goodat thrusting and busting
Noun: An object that is highly skilled at thrusting and busting