It happened when they were under attack by the Winter Soldier. Steve had pulled Natasha and Sam out of the car and they slid across the road on his shield. Sam rolled off, but the other two managed to stay on. By the time the shield slid to a halt, Natasha had her gun ready and Steve was about to get up. He'd had been lying at an awkward angle with his entire body half on top of Natasha's. It certainly wasn't intentional, but he didn't budge until he was sure it'd be safe to find cover. Before they could move, Steve felt himself grow hard and then, push into Natasha's backside. 'Shit,' he thought to himself. This was really not the time to be getting a hard on. Their lives were in danger for goodness' sake! The supersoldier shifted his body so that Natasha didn't feel it, but when she stiffened, he knew it was too late. "Are you kidding me, Rogers?" She hissed and half turned to give him an incredulous stare that would have been hilarious if it weren't for the situation they were in. "Sorry. It just...happened." Steve felt his cheeks warm in embarrassment. There was silence for a moment and to his surprise, Natasha rolled her hips back, brushing her backside against his length. "I'm guessing this started when I jumped into your lap in the car. Arousal from the thrill of danger. Nice." Steve swore that he was going to have a nosebleed out of pure shock. "N-Nat..." The redhead laughed and pecked her partner's cheek. "Don't apologise. You know I liked it, but now is just not the time." Steve nodded slowly, not exactly sure what to say, but he settled with, "Yeah." The Hydra agents were coming closer, so Steve and Natasha moved from their position. One fleeting thought came to Steve's mind, though. He knew his partner very well and when she said "Now is just not the time," he had a feeling that she planned to address the situation with his boner later. With that in mind, Steve was very determined to get them out of this, alive.