User blog comment:IamJakuhoRaikoben/Chapter 508: Pleasure and Agony, Review./@comment-5303512-20161031161120/@comment-1359322-20161102084009

Natsu and Gray blush too when Erza approaches them naked in the bath as seen in the Sun Village arc. Unless if you're implying both of them are in love with Erza like Mavis is to Zeref, i would say the blushing in those situation are different.