On the same principle as the word "Homesick"(Someone who misses home) : Pussick is a mix of "Pussy" and "Sick". It defines someone who is sex starved, someone who wants pussy.
Derived from the combination of pussy and asshole; a "pussasshole" is the after product of a taint ripping. Where the pussy and asshole become a singular hole.
Most common occurance is after a viscious double penetration.