Giv'er is seen on actor Tyler Labine's hat during the movie "Tucker and Dale vs Evil".
Giv'er is slang for Give her, and mostly used by hillbillies, hicks, and rednecks.
It can be used as:
Ima Giv'er the cock tonight.
Guy 1: Look at that HOT ass.
Guy 2: Go hit on that thang.
Guy 1: By tonight ima Giv'er my dick and bend her over and make her bark like a chicken.