I can HONESTLY believe that Pinkie doesn’t wear panties canonically in the EQG series based on one thing:
Her random, daring, and often oddball personalty.
Pinkie strikes me as the type who if asked why she doesn’t wear them would respond:
“Never really thought I needed them and besides, it makes using the ladies room super faster!”
I honestly think she’d walk around naked if the mood struck for the “fun of it all” and she knew she wouldn’t get in trouble.
On a more related note to this picture though:
I can TOTALLY picture her spontaneously fucking a boy if she thought he was cute and was horny at that EXACT MOMENT.
Meaning: that if 5 seconds past and she only thought the boy was cute and got horny 5 seconds later after walking past, she most likely would not bang him and instead finger herself in private or maybe even in public if the idea struck and she thought she could get away with it without anyone noticing.