Natasha would be lying if she said she hadn't used PDA liberally as a SHIELD agent and as Clint Barton's partner in particular. But then again, Clint would be lying if he said he didn't use PDA liberally as hers. Distraction, cover, decent cover for the fact that both of them liked having an excuse to pretend it didn't mean anything... Public displays of affection were a shoo-in for their work.

But the sincere ones? The moments they brushed hands or kissed softly or snuggled together on their downtime were generally kept behind closed doors. Generally.

(rest on AO3)