Part 4..
Same place, fairy tail 2nd floor.
Erza is still standing, her back against the wall and Mirajane pressed into her by Lucy.
Lucy is holding Mirajane head making her kiss Erza with one hand and holding Mirajane's ass with the other hand.
Mira and Erza tits pressed together, while Lucy is fucking Mirajane from behind.
All three girls are fully naked.