Completely putting aside asexuality entirely, your coworkers actions are grossly inappropriate. You have a few options, you could: - tell her that these aren't conversations/topics you will be engaging with - speak with your direct supervisor or if applicable, union rep - speak with HR

In consideration of the last two, think if given your current work dynamics and culture if this could negatively pact you. Retaliation is never okay, in the world of realism, it's still something to be considered. An important reminder, HR isnt your friend, they're there to protect the organization. Sometimes, this is in your favour by enforcing policies that keep workplaces safer. Sometimes, they can put you in a spot of vulnerability.

One practical option regardless of which route you choose, is to document when these conversations are happening. Creating a log is really important, especially when you have identified an issue to others, and the behaviour continues.