Because he knew she would fight and resist him all the way, Leonardo firmly held Amani at the back of her neck so he would be able to thoroughly kiss her, and Amani of course resisted at first before she couldn't anymore. Maybe because of her weak resolve or because of his insistence not to let her go.
When they finally decided to meet at an equilibrium point, so to say. Their kiss was rough, exactly like the first time they indulged in the act. It was as if he was trying to kiss her into submission and she fought back like she was refusing his dominance over her.
Then as suddenly as the kiss started, it stopped. His hand that firmly held her neck in place dropped to his side as if in resignation. They were both breathing hard while looking into each other's eyes. He expected her to fly into a rage and maybe slap him hard for forcefully kissing her after she had warned him to stay away from her.