Seeing Tony take on Natasha, Steve shifted his attention to Peter. He quickly moved behind him and started tickling his sides. Peter gasped and squirmed, letting go of Tony to get away from Steve. He quickly surveyed the scene, and seeing Natasha had Bucky handled he decided to keep his focus on Steve, to keep him from freeing Bucky. Peter quickly got behind Steve and then jumped on his back, wrapping his legs around his waist and his arms around his neck. Steve stumbled from the unexpected weight before Peter's hand attacked his sides. Peter was grinning as Steve tried to dislodge him. But Peter held on tight, and with the kid on his back Steve couldn't really reach him. "A little help Tony," he gasped as he tried to push Peter's hands away.