Cassie Told Diddy She Was Ovulating When He Asked for Freak-Off, Agreed to Kissing

Diddy asked Cassie if he had her permission to set up a freak-off ... and then she told him she was ovulating ... but appeared to agree on going forward with it if things remained PG.

The interesting exchange was raised Thursday while Cassie was being cross-examined by Diddy defense attorney Anna Estevao, who was going over text messages between the former couple.

Diddy texted Cassie, asking permission to set up "freaky fun," and her response was limited to one word -- "Ovulation" ... which sounds like a clear "no" to sexual intercourse. She previously testified Diddy did not want the male escorts using condoms with her during freak-offs.

Diddy texted Cassie, asking if they could "kiss a lot," and she agreed.

Cassie asked Diddy which hotel would they be meeting at, and testified she offered to go to a sex shop, the Pleasure Chest, to stock up on sexual supplies ... including lubricants and outfits.

Diddy texted Cassie to "have fun, impress me" on her way to the sex shop.

Prosecutors claim Diddy was coercing Cassie into participating in freak-offs ... but it appears his defense is using cross-examination to show things between them were consensual.