Wesley crushed his lips to Spike's with such force that he felt the bottom one split against his own teeth. He had enough cognition left at that point only to recognize that the taste of blood was present -- not to feel any actual pain -- and the brief flare of knowledge that Spike would be able to taste it as well made him even more aroused. He knew that he was starting to lose whatever rhythm he'd been managing until then, and desperately reached a hand between them to grip Spike's erection.