Sweet Sisterly Flesh by Amanda St. John

From the first chapter: ''Don't you think that Sabra is an extremely tempting woman?' said Milena. 'I do... I tell you what we'll do,' she whispered in a stage whisper in Davis' direction as she looked hungrily at Sabra. 'Let's seduce Sabra!'

Milena jumped up and pulled Sabra down onto the cushions beside her and began to caress Sabra's breasts as she sat behind her. She slowly reached around and brought her hands up under Sabra's firm breasts and with two fingers began to lightly brush back and forth across her nipples. Sabra arched her back, pushing toward the two fluttering fingers.'