mayonnaise
It's warm, sure but it's not hot and neither of them are nervous, no more than they usually are just being themselves; Mikey's awkward being and Frank's ability to always teeter on the edge of hyperactivity. But Mikey can smell the tang of sweat from both of their palms, taste it at the edges of his tongue. It's gathering in the crooks and cradles between their tumbs and forefingers where they touch, hands crossed in something more elaborate than a brother-grip but close (and they're pressed so, so fucking close). There's apple-smell on Frankie's hands as well (the not-quite-believable kind that sticks after you eat sour gummy snakes for lunch because they're the first damn thing you lay your hands on at the rest-stop) and on his breath there's more apple, and Gatorade, and all Mikey is trying to do is find something to say. Desperately looking for something that isn't "I love you," isn't "god do you have any fucking idea how much you mean," isn't the kind of thing he wouldn't even say during sex. Frank noses at the top of Mikey's head where it's tipped down, unconsciously staring at the familiar creases of Frank's knuckles, slipping-sliding in and out of focus. Frank's hair is soft against Mikey's cheek. Things feel soft and bleached like old t-shirts and pairs of jeans.