Gaine hardly had any experience in interfacing. He wasn't out in the world much, not when he was off duty, and so whatever he knew he learned from studying himself. It was similar with the other mechs he worked with. They would study diligently and then when they didn't understand something, they would ask either Might or Hameda about it.
About interfacing, though, Gaine didn't think it was appropriate to ask either young men about it. the thought sent his circuits sparking in embarassment.
Even if Gaine wasn't too sure about the idea of interface, he knew the gist of it. Humans referred to it as "sex" and it was usually between male and female of their species. It was not limited to that, however. The express team had been designed without gender in mind, and Hameda had explained briefly that they physically mimicked both human genders, in case either robot identified with one or the other. Gaine had somewhat investigated the claim, curious one morning and had honestly almost run to Might in fear he had done something wrong. He'd just innocently been pawing at himself when it felt almost too good, and his cord had pressurized strongly enough to knock his codpiece off. The appendage scared him at first, and he'd frozen, biting his lip and staring. The tip leaked and the base throbbed, and he couldn't seem to will it down. Gingerly touching the length, Gaine had gasped and immediately wrapped his servo around it. It felt… good enough. And safe. He squeezed a little, and whined at the feel of it. Slowly stroking at the cord had gotten him off messily, but Gaine had since then researched how human males, er, functioned sexually.
It seemed easy enough. Kind of.
Gaine was now giving his counterpart a crash course in the matter, shyly explaining where to touch and what felt good. Black Gaine was a quick learner, touching Gaine earnestly with an adorably determined frown on his face. The black mech's glossa peeked out from the corner of his mouth, a little habit. He was jerking Gaine off, when the other mech stopped him and leaned close, directing him to lie back. Black Gaine obliged and flattened against the concrete, his knees bent and his legs spread wide. Gaine moved between his thighs, rubbing his stiff cord against Black's panel. The mech groaned and bucked at the movement, squirming and arching. Gaine smiled, kissing at Black's chest and neck, all he could really reach. It took him a little while, but eventually Black released his valve panel, the interface dripping onto the ground. It was here that Gaine had no prior experience and, unsure, thrust himself in to the hilt. Black yelped, optics flashing painfully and Gaine nuzzled him apologetically. He waited patiently, pressing kisses to the tip of the other's train chest. Eventually, Black Gaine whimpered, moving his hips. Bucking into his twin, Gaine moaned loudly, chasing his overload. Black Gaine crashed his hips against the other, mimicking his volume, until finally both mechs crashed, scraping their paint as overload hit them.
Black onlined first, inspecting the white streaks all along his bumper. That was… noticeable. Might would not be pleased if they showed up like this. As it was, Gaine remained comfortably on top of him.