This question already has an answer here:

Some of my trousers can't keep the fly up. It's annoying and sometimes awkward to get it up, particulary in public.

How can I prevent them from opening while walking?

One solution I already know is to fix it with a paperclip, but then, when I go to the restroom, I have to "unlock" this fixture which is annoying again.

marked as duplicate by MrPhooky, kenorb, Jon, vladiz, Mooseman Feb 24 '15 at 11:54

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

Browse other questions tagged or ask your own question.