Byleth's wordless moan should be answer enough to that question. He rides that cock up and down a few times, enjoying the unique texture before pulling the other to penetrate alongside the first. It gives some resistance at first, but once the head pops in, Byleth thrusts downward, taking both in at once.

He practically howls for the sensation, shoulders trembling as he tries to steady himself. His eyes look distant, taken in by the pleasure entirely.

"Fffffhhhhkk-" The word, if it could even be called that, comes hissed through his clenched teeth.