Really Steve was probably prepared to go however far Tony and Pepper were willing to lead him. He knew absolutely nothing about sex and thus wasn't really sure what to do with his hands other than move them to rest gently on Pepper's shoulders, though he was supporting the most of his weight on his knees. Finding he rather enjoyed the feel of Pepper's lips against his own, Steve tried to press them together more firmly and even let his tongue snake out a little to rub gently against Pepper's lower lip.