Nightmare Sisters (1988) 
From the sublime to the sexily ridiculous! 3 nerdy sorority sisters find themselves alone for the weekend and invite the only boys they know over to the house for a small party, they end up holding a seance (as you do) and become possessed by a Succubus.
Contains quite honestly the longest gratuitous "3 naked girls in a bath tub" scene I have ever seen, fantastic! If you like boobs (in three different size variations, something for everyone) then you're in luck, you'll enjoy this
After their extended soap session the three girls are hungry and only a certain oral activity will sate them, just watch out for those razor sharp teeth!
I find it hard to actually recommend this because I'm fully aware that my taste levels are questionable and this is clearly not a well made film, but it's campy, and sexy and has a Linnea Quigley music video (she's performing her own original song) right in the middle which is excellent
Watched via the 88 Films triple bill collection
'80's Scream Queens'