This definitely wasn't Jim's first kiss. He had been careless with his lovers (if they could be considered that) over the years, so careless that he had no idea how many he had. He only took what he wanted from them and left without a second thought. None of them could hold his attention or interest for very long. All of them were one-time flings- except for one. Sebastian Moran. But that relationship was as twisted as they come. Years from working together had produced a demented version of a partnership, and Jim wanted out of it.
The feeling of kissing someone who could understand him was better than anything he could've experienced with someone else. He tightened his grip on Sherlock and deepened the kiss, staggering against the man as he almost lost control. Vertigo swept through him and he had to hold on to Sherlock to steady himself.