This is a term used to when going to bed with someone. To make hay means to copulatein bed with a significant other, often not only for sex but for sleep too.
To take advantage of a brief opportunity while it is still there. To not waste time.
The saying comes from farming communities. There would often be only a short time in which the hay would be ready to cut- reap too soon, and the hay would be too green. Reap too late, and you run the risk of rain ruining it all. Still very good advice.
I just got a good job for the summer- I don't know if I'll have one this fall, but I'll make hay while the sun shines and save up for the winter.
To take an opportunity to do something when the time and conditions are near perfect or available.
From agriculture, when farmers gather the long grass growth of summer to dry it to produce hay as winter feed for animals; The best time to cut and dry the hay is during sunny days.
A:"There's a sale at K-mart this week - You wanna see if the have something for your sister's birthday?"
B:" Sure - Might as well make hay while the sun shines, and get her something at cut price!"
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.