You are drawn back.
Earlier, you saw Carrie get into a taxi, dressed like she was going out. So you watched her house, noted which lights she'd left on; the front porch, the kitchen, and the laundry at the rear of the house.
After midnight, the front porch and laundry lights turned off, and the light in her bedroom switched on as you watched from your second story window. Carrie was home.
Once again, darkness finds you standing between two shrubs, hidden from the street by the shadows. It is a warm night, so the slight breeze is welcome as you peer through the gap in the curtains.
Carrie has already gotten undressed by the time you arrived, so you first see her coming out of the ensuite bathroom. To your delight, she is already naked. She is brushing her hair, and as her arm moves her firm breasts jiggle, nipples tightly puckered. She laughs, and turns and says something in the direction of her bed. She is not alone! You hadn't realized she had company, and quickly look over towards the bed. Lying back on the pillows is a beautiful woman. She has long blonde hair, and her body is firm, with smooth tanned skin. Her breasts are smaller than Carrie's generous cleavage, but still a good size, with paler, small nipples. You cannot see her pussy, but her legs seem to go on forever. You recognize this woman; her name is Sara. You have seen her before with Carrie; they seem to work together.
Sara smiles and holds out her hand to Carrie, who puts the brush down and walks over to the bed. She pauses near the bed, and the blonde runs one hand up Carrie's smooth leg, before catching her hand and pulling her down on the bed. They laugh, and, now lying next to each other, Carrie runs her hand down Sara's back, and starts gently rubbing her firm ass. Their legs are intertwined, and Sara's slides sinuously up and down against Carrie.
They kiss, and instantly your cock is throbbing. You free yourself and groan with pleasure as you watch the two girls, one blonde and one brunette. Carrie lightly nips Sara's bottom lip, and brings her arm around to Sara's breasts. You stroke yourself as you see Carrie's glossy red nails gently rolling Sara's pink nipple between them, then spreading her hand and massaging the whole breast. It fills Carrie's feminine hand, and you can imagine your hand holding that breast instead of Carrie, feel its fullness in your palm and the softness of the skin under your fingers.