Stiles swallowed hard when Derek pressed his hard cock against Stiles' leg. It had turned on Derek to torment and have Stiles hard and ready for him. That thought alone could have made Stiles come in that moment.
Taking a breath Stiles moved back slightly from Derek and he tilted his head back to expose his neck. Stiles had done his research on wolves and knew the sign of submission. The leash and collar wrecked the view of his exposed neck but it would have to do.