@awnlee jawkingOften, you'd squeeze someone's balls hard, as the pain causes you to momentarily lose the urge to come, so you can then last longer (taking the edge off, as it were).
You could also massage the balls, but while some get excited by it, many others aren't as fond of it, so often it takes a bit of experimentation with your partner. Just like not every girl is the same, so too not every guy is, though they are remarkable similar, as that's part of the whole mating dance.
Guy's are typically the aggressor as that's what's always kept the species going, and frankly, in terms of genetics, violent rape is basically the same as hours of love making, in a 'continuing the species' framework. It ain't pretty, but it's till true.
This is especially true, as often, if you push the girl, you're essentially demanding something, and thus, knowing it's essentially an accepted fate, many will simply accept it, rather than simply say no or using a safe word. As every guy knows, "No" doesn't mean much in the throes of sex. An empathic "NO!" is different, but again, it again, it ain't the same as threatening to crush a man's ball. Which IS a definitive mood breaker. ;)
Which also emphasizes how having 'safe words' is so essentially, but again, they need to be practiced, as in the throes of passion, it's amazing how much you're thinking and concentration is impacted, and many simply forget the safe word. Signaling it's probably best to ease off, but who can really argue with an insistent prick, as they have a mind of their own (i.e. their 'little' head).
The same is true for ass play. Yes, for many, shoving a finger up there ramps up the excitement, yet for others it's like tazering their balls! Especially if it's just ass play (i.e. a finger tip), as then, there is NO prostrate pressure at all, which also trigers a much more powerful urge to ejaculate.
Which is where the play comes in, so you can get used to those worst trigger moments, further emphasizing the need to remember the damn safe words. As nothing spoils the mood quicker than an unexpected pregnancy!