Mrs. Mac and Mrs. Kelly move in together after Mrs. Mac burns her house down. Yes, we know this picture isn't from that episode, but look at them together.

It's Always Sunny in Philadelphia Season 6 Episode 6 Quotes

Dennis: Mrs. Mac has a unique and earthy fragrance.
Mrs. Mac: I smell like shit.

Frank: Deandra will take care of me.
Dennis: Dee's not gonna take care of you. You just chased her out of here with a pool cue because she had a little cough.