Butt Fuck Bukkake (2010) comes to mind with Beverly Hills, Jamie Elle and Chastity Lynn.
https://www.iafd.com/title.rme/title=butt+fuck+bukkake/year=2010/butt-fuck-bukkake.htm

There's also some of Legalpornos scenes particularly the Anal Endurance themed ones that have a lot of this:
Ria Sun Anal (mostly Double anal) Endurance 6on1 with Facial /See description for more info/ GIO407 - possibly my favourite Ria Sunn scenes
Anal Endurance with Sasha Zima No Pussy, Anal / DAP / TP (DP before the end) / More info in Descript
10on1 Double Endurance - July Sun /See description for more info/ GIO343 - "10 Guys! A normal Monday here..."

Then there's the "is Indestructible" series which is 2 back to back anal focused gangbangs. That's a lot of anal! Just have a search for indestructible on the site.
I've really enjoyed the way they get a girl fucked anally in standing doggy against a wall with the train of guys queuing up behind her in a lot of their latest scenes.

Would be good to hear of fellow members favourite scenes that include extended anal fucking. Theres a lot of gangbang films out there but it would be good to have a compilation of:
1. The single longest continuous anal fucking in a scene
2. The longest continuous anal fucking by multiple guys with minimal interruption between

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