Renji knew there was no chance of stopping himself; there wasn't even a strong desire to do so. When his palms began to sweat and his mouth went dry he knew there was no other option but to allow what was intended.
So, when Renji felt the panic grow in his stomach like leeches sucking on blood, he didn't even stop, not even for a moment to consider what would happen once he was done.
Pushing his lips to Ichigo's he expected that perhaps his ego had finally gotten the best of him. He hadn't expected Ichigo to kiss back.