GF can never come more than once. Any chance we can teach her to do multiples? She can come from oral, fingering, sometimes just from grinding.  But once she does come, she's all done. She says it's too "sensitive". So we have to be strategic when we do it if we want to make it last. She'll still have sex after she's come but not for very long, and she prefers to finish me off since her pussy is so sensitive.  Are we stuck with this?