I once knew a girl many years, since she was a teenager, only considering her romantically once she grew into a woman in her 20s. I was in an age awkwardly in the middle between her and her mother, and they were both in my congregation. At one point, after a group picnic, I drove the daughter home, and we started passionately making out before she finally exited my car to enter the apartment she shared with her mom. A few nights later, the mother gives me a call, and in the longest conversation we'd ever had, she confessed to having her own feelings about me. I was in a sad state of mind at the time, very horny and vulnerable. So, when the mother suggested that I go over to visit her that night, I was sorely tempted. It would have resembled a "Mrs. Robinson" situation from THE GRADUATE (1967). The horn-dog side of me imagines the thrill it could have been to have mother and daughter in bed at the same time. What a confused scandal that might have caused if I got them both pregnant!
On a different occasion, I did get to actually have two half-sisters at the same time. They visited me at my apartment, and both knelt naked, side-by-side in Doggy position on my living room floor. It was such kinky bliss to be caressing the soft white flesh of one sister's butt while I was fucking the other's warm vagina. It was important that it be an FMF because I wanted either sister to be fully aware as I fucked the other. I guess the only incestuous connection was me as their common sexual conduit. It was such ecstasy to switch my penis from one sister to the other. Ultimately, I had to decide which of them to pump my semen into. I chose the younger one. But I should have started my ejaculation inside the one sister, clamped down on my dick halfway through, and then finished cumming inside the other sister.