His brow arched and he made a thoughtful sound as the kiss passed from Steve to Bucky to Clint, but he nodded, "Alright. Let's make this interesting from the start. When I say 'hold' no one moves, except as directed, until you get the all clear again. Understood?"

Mostly he was just going to let them wear themselves out a little before joining in, otherwise he'd be completely useless after five minutes.