Stiles eyes went wide at the soft kiss to his hands because it was unexpected and Derek looked like he meant to do it. The single action sent Stiles' mind a buzz with thoughts but he pushed them all aside before he could really think them. Knowing he might regret it because Derek could possibly reject him again but in that moment not caring, Stiles leaned and kissed Derek.
The action was sudden but the kiss was soft and gentle, their warm lips brushing against each other, as Stiles' heart fluttered.