If Tony had any warning or precedent for this he might have been able to fend Cap off with a ego-shattering backhand. Instead, Cap's five o'clock shadow was assaulting Tony's lips (far too delicate for an attack of this nature) for a solid and excruciatingly long second as Tony's brain misfired, still asleep and dreaming of Pepper and not prepared to leap so dramatically into physical violence. If he had the presence of mind, he might have considered the casual ease of Cap's approach and the possible implications, but for the moment Tony was more than happy to shove him back then hold him fast by the collar while he pushed himself up and scrambled back, bending a knee between his heterosexuality and Rogers' misguided affection.
Deep breath. Nothing to be angry about. Flattering, really. Still holding Rogers, Tony insisted, "Let me catch up first." He had a bottle in his desk; it wouldn't take him long. Much more intriguing: a super soldier clearly had a way to get drunk and he needed to share the secret because Tony had his own Captain America that could use a little loosening up. Tony made the mistake of licking his lips before abruptly releasing Rogers to wipe them instead, leaving his knuckles pressed to his teeth and staring over them at Steve with a particularly hunted look until he conceded to give Tony his personal space back.