Martin expects — he doesn't know what to expect. More of the same, more or less; an escalation of some kind, either gradual and patient or sudden and surprising. There's a broad range of possibility, and the unpredictability is half the fun. But he still feels as though he has a reasonable idea of the techniques at John's disposal. As if all the surprises thus far have met some sort of unspoken quota, and there couldn't possibly be any more.

So it's a bit ridiculous to be shocked when John uses his tongue, especially considering it isn't even the first time this session. But that earlier move had been playful, mischievous, and almost incidental, like he was just poking at Martin to get a reaction rather than actually testing any waters. As if John's ever been known to try anything only once.

This time, though, it is markedly different. Thorough and attentive, a completed thought compared to that earlier notion. John so rarely employs his tongue beyond talking that Martin would never have thought to consider this specifically. He would, if it had ever occurred to him, have assumed it might be too much.

But apparently not. And it's fucking great, is the thing. John is as dexterous here as with his fingers, and in concert with that gentle, persistent suction, it's sublime. Martin's back arches sharply as he nearly chokes on a sudden inhalation, cutting himself off mid-cry and gasping instead. His fingers twitch, his hold on John tightening just a little, a gentle pressure that might almost seem subtle if not for his trembling.

"Oh, fuck," he blurts when he has his voice again. He relaxes his hands again, letting his touch simply be warm and steady. "Oh god, yes."