It depends on the context and the relationship between the couple. In a very private, trusting, and consensual relationship, sharing such stories might be a form of sexual communication. However, it should always be within the boundaries of respect and legality.
Tell them firmly that such stories are not acceptable in the current context. For example, 'I don't want to hear this. It's inappropriate.' If they continue, you may need to remove yourself from the situation.
Perhaps she is testing the waters to see how you would react to more adventurous sexual ideas. It might also be that she has a newfound confidence in the relationship and believes that you two can have a more open conversation about sex - related topics. However, it's also possible that she doesn't realize it makes you uncomfortable if it does, so communication is key to find out her real intention.
First, stay calm. If you're comfortable with it, you can engage in a conversation about it. If not, gently let her know that it makes you uncomfortable.
Travel experiences are also wonderful alternatives. You can share about the different places you've visited, the unique cultures you've encountered, the beautiful sceneries you've seen, and the interesting people you've met during your travels.
Well, you could try to educate yourself about different aspects of kinky sex to better understand her preferences. But always prioritize consent and mutual enjoyment. And don't be afraid to take it slow and build up to more adventurous experiences gradually.
It depends on the nature of your relationship. If you have a very open and adventurous relationship, you might laugh it off or even engage in a healthy discussion about sexual fantasies in general. But if it's not something you're used to, it's important to set boundaries. You could say 'I appreciate your openness, but this is a bit too much for me right now.'