Steve really shouldn't have been surprised. He knew Tony had done some really random, stupid shit as a kid. (Not limited to several different drugs and once he apparently created a Sentient Toaster, but that was besides the point)
But Tattoo's? He'd always seen tattoos as tasteless, though he'd never said anything about anyone else's, it was their choice to disfigure their body if they so choose.
...And then, by accident, he had seen Tony's tattoo.
It was small, almost...tasteful. On Tony's lower...lower stomach, right at his pants line. It was a small 'A' with two little wings, flanked by a red/white/blue star on each side. It was something that unless you knew intimately about him, no one would probably get...but he knew.
He grabbed Tony, ignoring the man's shout of surprise, and dropped down, yanking the others towel away to look at the tattoo, before looking up.
What he was going to say disappeared at Tony's red face. "...Why are you bright red."
"I'm naked, Capsicle. Take a wild fucking guess."
Steve blushed bright red and stood up. "You have a tattoo."
"You're very observant."
"...Its of me, isn't it?"
"...No." He said, looking away with something like a blush across his cheeks, and Steve grinned, moving closer to him.
"You have a tattoo of me...on your Pelvis."
"I was 17 and drunk okay?"
"You were inebriated, and i was still what you chose to get a tattoo of?"
"Fuck you." Tony snickered, looking away.
"...Suppose I'll have to get a matching one now too...Maybe a little Arc Reactor on my chest?"
"...You hate tattoos."
"I love you more than I hate tattoos."