The only term I could think of is defeminization.
It seems like most people understand what emasculation is and the things that cause it.
What are some examples of situations that can cause the feeling?
Edit: changed effeminization to defeminization.
Masculation would be the opposite of emasculation. Masculine women are seen as butch, bull dykes, stuck up c*nts, etc., the same way feminine men are seen as weak, gay, sissies, pussies, etc.