My experience.
If between honesty (that doesn't make your butt look big, your butt makes your butt look big) and survival (sorry, I wasn't paying attention) then survival always wins. You don't want an honest answer (you can't handle the truth!) from a man with a question like that, you want something he is incapable and unwilling to give - a critical yet sensitive and intelligent opinion. That's asking a lot of a guy. Ask a girlfriend/mom/sister.