His cock was in heaven.  Actual heaven.  His hands instinctively held her close to him, not wanting her to stop.  Not wanting to let her stop.  He could feel his knees threaten to buckle beneath him.  When the time came, he said in a breathless voice, "I'm gonna come."  He wanted to warn her in case she didn't want to receive a mouthful of his seed.  A part of him didn't want to give her a choice but just make her take what he had.  It was a violent thought and it frightened him a little.  It also succeeded in turning him on completely and soon his cock was just on the verge of exploding.