I had this problem with my last girlfriend. She got a little insecure but we eventually worked around it. Not using condoms if possible is a good solution, along with changes of position to more flexible ones. A few times we'd have sex and then when she was satisfied she'd "finish me off" (I had no way of knowing how to not make it sound weird) using other means which was pretty much, ya know, the bomb.
If you're really worried go see a GP (or whatever they call them in other countries), but until then I'd say best solution is to experiment. Don't go full karma sutra, just keep an eye and an ear out for any ideas that you'd like to try.
If you're really worried go see a GP (or whatever they call them in other countries), but until then I'd say best solution is to experiment. Don't go full karma sutra, just keep an eye and an ear out for any ideas that you'd like to try.