Thanks for elaborating but I think I'm still not really convinced what 'toxic femininity' is (or masculinity either). Because, going on your example, stereotyping and generalizing here, men tend to want to prove they're men by doing stuff to fit the box. Women don't usually need to do stuff to prove they're feminine unless they want to prove they're just as good as men so...
or, that they feel they're not feminine enough? One example off the top of my head: a girl may feel she isn't feminine enough because her high school friends have had boyfriends, but she hasn't so maybe something is wrong with her. So I guess, exceptions but not the rule.
I'm more inclined to agree with MK_Wizard that the term is misused. Gender roles, misconceptions, expectations, stereotypes are what makes ideas of femininity and masculinity toxic, not the other way around. Because one can argue, what is wrong with a girl wanting to be girly because she likes being girly? And, what's wrong if a girl doesn't to be girlly because it was never in her nature to be one? Neither is wrong or toxic, but it can become one based on who is trying to impose it.
Using the Mean Girls movie that someone mentioned on here is what I'd consider an example of females expressing their aggressions. Girls are normally nutured to not show physical aggressions as boys from a young age (actually, almost everything non-physical), which is why they tend to be more passive aggressive because if you can't express it by punching someone, it's going to come out one way or another.
Also, for those that don't know the Mean Girls movie was based on the book Queen Bees and Wanna Bes by Rosalind Wiseman, a parenting book helping parents help their pre-teen and teenage girls as they navigate the cruel of being a girl in a girl's world. You don't need to be a parent to enjoy it 