Gf is finally into it, but i'm a bit scared advice needed!

We found that the time to have the conversation was when we had just had sex and had both cum. Then you take the sexual excitement out of it. It may sound odd but you do need to have a conversation when you are both very 'sober' and get to some real practical issues - We would ask some real questions like.. so what do we do with him once he has cum and I have cum? How would you feel if you cum and are not longer aroused but I want to carry on with him? I know it is not very exciting but the reality can be very different from the fantasy and you have to do a reality check. As has been said in this thread..you cant un-fuck after it has happened. I have seen it happen where a husband 'lost it' when the guy started fingering his wife - lucky he was smart enough to know what was happening and stopped and left. They left and we never saw them again. Just be prepared for some unexpected emotions.