Everyone has come across a shit sniff, it is the sound men make to inform other men in a public restroom that they are currently in the process of dropping a deep sea bog diver. It is simply a very short and abrupt sniff, it is clear that because of it's short duration a shit sniff is not used for the pleasure of sniffing shit, it is merely a warnig to others that the process is occuring.
Next time you are in a public toilet (and i know that sounds weird) have a listen and eventually you will hear a shit sniff but you do not mention it when you are in there you'll put them off their stroke.
Stiff Shit commonly used in conjunction or in replacement of too bad. Used when someone is complaining of something or being a little bitch about a situation.
Example 1:
Boss: Mate I need you to start work a bit earlier tomorrow to get this job complete.
Employee: Oh but boss I really was looking forward to a sleep in tomorrow morning.
Boss: Stiff shit, see you at 6.
Example 2:
Veruca Salt: Daddy, I want another pony.
Verucas' Dad: Stiff shit.
It is said of the situation where a person has the bad luck to make contact with his testicles against an undefined surface or object, intentioned or not.
Given the nature of the word, it is more appropriate to design cases where the interaction is made with a moving object, for example, a ball.
Although it is extremely painful for the victim, it tends to be considerably funny to people who witness it.
Today in the baseball game the pitcher took a nutshot; the baseball hit him in the nuts.
Man, I just watched the funniest nutshot video ever.