Steve was now a 'fugitive', on the run for SHIELD, and you were helping him stay hidden, giving him hints on how to act normal and not suspicious or stick out.

You were on the escalator with him when you saw a SHIELD agent going up the other side of it, about to spot you. You turn to Steve.

"Kiss me."

"What?" He says, seeming rather embarrassed.

You roll your eyes.

"Public displays of affection make people uncomfortable."