His sinuses.

Right now, in the middle of this private hospital room, as the two of you wait for the gyno to step in, as you hold his hand in a vice grip, each squeeze simultaneous with each contraction panging through your lower half, nothing is annoying you, the you that is in pain, overstimulated and on a light trigger to anything, nothing is annoying you as much as his goddamned breathing.

In, out, in, out, you could hear the damn air rush in through his nostrils and then him exhale.

"Your breathing's too loud." you mutter, breaths short and uneasy. He turns to you with an amused look on his face.

".. my apologies, I think..? I'll.. try to breathe quieter, love.. yeah?" he chuckled, confused as what you wanted. Though no matter what you desired, right now, he'd do anything you ask.