Breastfeeding/sexual stimulant problem

My younger sister had a baby 3 months ago and called me and said she's having a problem breastfeeding. Basically, it sounds like she was into her husband suckling her during sex or maybe is just into a ton of breast kinky stuff before her kid was born. Not unusual to me. Then she started crying and saying when she's feeding she gets "wet" if you catch my drift. She was VERY clear that she has NO pedophilic feelings toward kids -which I obviously never thought she did, and she is struggling to train her body that nipple stimulus doesn't mean sex is about to happen. She's super ashamed and I felt so bad for her. I told her I kinda dealt with something similar but I just ignored it when I fed my son. Eventually it didn't bother me anymore and frankly the chapped nippled hurt so bad there wasn't a problem shortly after he was born anyway. So maybe she found out about nipple balm before I did because she didn't mention that or pain. I never cried about it though and it's obvious it's disturbing my sister more than it did me. I'm not sure what to tell her besides give herself more time. Did anyone else deal with this and have some advice?

Also posted anon because I don't want people to think I'm a troll.