Is this usually said to men? Can we tell a woman to "sack up"?

i don’t think people say that where i live lol

Nut up or shut up.

I’ve never heard this used. US, lived on the west coast and in the south. For the first meaning - I’d say you bag groceries, not sack up groceries. For the second, which is the one you’re asking about - the phrase I usually hear is “man up,” which is dated and not recommended. Maybe “grow a pair,” which is still a bit dated but not as much. “Grow up” is a more modern alternative although it does come across less forcefully. Never heard sack up. I’d understand it based on context but would think it pretty weird. Generally, “vulgar slang” is something to avoid. I can’t really speak to how it would be received to say this to a woman, since I don’t live in a place where it would be used at all

The concept underlying the second meaning is that men have testicles and are therefore naturally more brave and assertive. Thus, men should be assertive and assertiveness makes you a man. In general, you *can* use these gendered expressions with anybody. But you should be aware some people may find them offensive or stupid. I do. Anybody can be assertive. And being assertive doesn't make you a man.

I’ve never heard this phrase. But I don’t think it would be wise to say to a woman.

"Strap on a pair" is the way I most often hear this. Yes, you can say it to women, just be aware that it's crude language and only really appropriate between friends.

In my area the phrase is “man up” and you would not normally say this to a woman for obvious reasons

Never heard of this

The first definition is an older phrase that you shouldn't use. Instead people would use "bagged" or "packed". The second definition is what people would interpret it as, and it's not really something to use either, and isn't really something you'd ever say to women. The more common phrase would be "man up", which is also not something you should really be using. It's a phrase that would make people think you are sexist. Mainly because it's generally sexist people who use the phrase. If you were looking to say to someone to be more assertive, you could say "grow up" or "toughen up". As in "You need to grow up already and ask for the raise" or "You need to toughen up and tell them they're wrong".

Hard to say. I have never heard this phrase in any context.

Never heard of this.

If you said this to me I would just be confused and give you a weird look. I’ve never heard it before, so unless you’re in whatever region that’s from it isn’t going to mean anything to most people (US- lived rural east coast, urban Midwest, suburban west coast)

Never heard this in my entire life (from England)

Never heard this. But i've heard "grow a pair". Of course the "pair" here is a ballsack, but I can see it being said to a woman

It's not really used much at all. I'm familiar with the expression but have basically never heard anyone use it. It's a mildly sexist expression for exactly the reason you described. Testicles have gotten conflated with bravery/toughness in English expressions. Thus expressions like "Grow a pair" (indicating someone should grow some testicles to toughen up), "man up", etc So I would generally avoid these expressions.

I mean you *can* say anything to women. Whether it will be well-received is another story.

I’ve never heard “sack up” being used where I live in the southern US. People say “man up” or “grow a pair” here. That being said, you shouldn’t say something like this to a man OR a woman that you don’t know well or in a business/professional setting because it’s very rude and vulgar.

I’ve never heard this in my life, I would not use it