https://gfycat.com/FamiliarCourteousAndeancat
more general xxx photos in category SauceForScience
from #thread (https://reddit.com/r/SauceForScience/comments/4a7va7/eight_girls_giving_head/) by @MarinSkt
Here's an album of girls giving invisible head (among other things)
imgur.com category @anthonyridad