I have quite a ually graphic question.?

I have recently decided to become ually active for the first time. I remained abstinent for so long for moral reasons I guess. I have yet to actually have , but I have done other things. My question is, why whenever my boyfriend fingers me, do my fingers tingle for about 10 minutes afterward? It is kind of pleasurable, not painful, but it's odd. Sorry that the question is rather graphic. Thank you/