Because you don't have to be full of sperm to be all ouch-filled in your pants.
It's definitely a phrase you've heard before, probably when you were in elementary school listening to boy children swaggering around pretending like they had testicles that had already descended.
It's uncomfortable to become sexually aroused and then to have the action stopped by say, a Pokemon Go alert or a suddenly urgent need for chimichangas.
The reason for that discomfort is vascoconstriction.
It happens to both men AND women. This rush of blood leads to a swollen, pressure-filled feeling in the genitals.
Normally, having an orgasm releases that pressure. But when you don't because all of the sudden he remembered that he was supposed to pick up his dog from the vet, it leads to a dull, uncomfortable ache.
"I told you," you will grumble while putting your pants back on while he looks for his car keys, "being 'too cute' is not a condition worthy of taking your dog to vet, STEVE."
But ultimately, his love for his dog is part of why you love Steve, so you put up with it.
Did you know that 47% of all women don't know that pink balls are a real thing?
It's not that shocking, when you think about it. Unfortunately we live in a society where a man's needs can and do trump those of a woman.
Plus I know there's a lot of "fake science" circulating about blue balls. "But babe," says Ricky, the worst guy ever, "if I don't orgasm now my balls risk exploding because of my powerful, powerful, sperms."
That's just not what is happening. Women don't NEED to ejaculate to climax and we still can feel the discomfort and annoyance of a sex session being interrupted.
Side note, I'm so glad you left Ricky for Steve. Steve just seems so nice.