Ruby was lying down on a couch wearing a red bra and panties on a calm afternoon.
"Hey there, Ruby." said a voice.
"What do you want, Sis?" asked Ruby, looking up at her older sister, Yang, who was in just a yellow bra and panties.
"Oh you know," she said with a devious smile, "to spend time with you."
Yang grabbed her sister and opened her mouth wide. Ruby's eyes opened as wide as wide as they could once she realized what was happening. However, part of her just wanted it to happen. Ruby's body just slowly went into her sister's mouth.
Ruby felt Yang's saliva on her head and then her neck as she slowly went in. Yang covered all of her upper body in saliva. Ruby felt slightly uncomfortable because of this, but managed to remain still. Yang enjoyed the taste of her younger sister as she swallowed even more.
Yang licked her chest really good, which caused Ruby to giggle and then slide down into her older sister a great distance. Ruby's leg's stuck out of her sister's mouth. Yang swallowed past Ruby's knees then pushed her feet into her mouth.
Yang swallowed again, and Ruby fell into her stomach. It was wet, slimy, and warm in there. Yang took Ruby's spot on the couch and began to rub her belly. The walls of Yang's stomach wrapped around Ruby like a blanket. Then, her digestive fluids started bubbling.
"How is it in there?" asked Yang.
"Warm and kinda cramped." answered Ruby.
"Cool!" responded Yang, "I'm gonna digest you now!"
"W-what!?" responded Ruby.
"You didn't run away." said Yang, "You will be at my boobs in a few hours."
Ruby wasn't all too happy about this, but there was no way out. She would be fully digested by her sister a few hours later, when Yang's boobs were even larger.