To perform a backshot, you gotta screw somebody from behind, bareback. either hole will do. Now, when you pull out instead of blowin it internal-like, and jizz on her back, THAT'S a backshot.
A good one will hit her hair, a great one will hit the far wall.
Watch any generic white peopleporn, and I'm sure you'll get a great example in no time.
When the female sinks in or arches her back while on her knees and hands on the floor. The male proceeds to enter her vagina while she's in that position. It is recommend that the females throw their ass back while in that position and the male grabs her hair and slaps her ass a few times while saying dominant words.
Backshot wind, (or Backshot Air) is the unique smell which wafts into your face when having sex from behind, usually encountered with thiccgirls and BBWs.
"Man I was having a great timeclapping those cheeks, til I got a whiff of that backshot wind"