I'm pretty sure it might have been on a oneshot collection but I know it was rated MA and I remember Kags and Sessh were at a play when she goes into heat and Sessh mates her and impregnates her on the balcony. If anyone else remembers this one I would greatly appreciate it!

Is it Exhibitions by sesshys_jaded_samuri? Check out Chapter 3 it may be what you're looking for...
www.dokuga.com/fanfiction/story/42/1



A collection of oneshots featuring Sesshomaru and Kagome and their bold displays of affection... in public places. NEW CHAPTER ADDED - Now serving... PUBLIC DOMINANCE
Rating: MA - Universe: Alternate - Status: Complete - Category: Oneshot Collections - Genre: Erotica, Romance - Updated: 10-31-09 - Created: 04-26-08 Chapters: 6 - Reviews: 35 - Words: 29,681 - Reads: 58,410

YES! That would definitely be it! Thanks so much