More time passed for you (Jacob) and Samantha. More cycles of fun, exploration, and feedback for the U.S. Marshals while waiting for your trial. You both got increasingly more creative on how you handle yourselves, and sex was no different. Oral sex, sex in various positions, using your limbs and other parts to try and come up with ways to stimulate each other. Samantha even attempted rubbing your ovipositor while you were laying eggs, and was definitely a good experience. You had plenty of time to come up other ideas, but finally you both attempted an idea you put off.
Sex with other house flies.
You've encountered them of course during your explorations, and thanks to your size you could easily shrug off any advances they made, and there was many due to being a "prime" example of a female House Fly. Samantha had no issues, as a male house fly did the courting and she did not care for them. But today, you both tried it out. You would split up to find single flies, trying to avoid groups when possible, and soon found a male fly that most certainly wasn't the prime example that Samantha was, but it would do.
You knew there was a courtship ritual, but you knew you were "sexy" as far as a female house fly was so you just landed near the male fly on a surface, turned your back to it, and hope it got the same idea as other male flies' attempts with you. It did, and soon it mounted you.
The house fly did its business, as robotic as it was. Thanks to the custom changes provided for yourself, it was still enough to give you a buggy orgasm. However, the male was just doing what nature intended, and just deposited its load in you and soon flew off. The whole experience was nothing special, but at least you could have a "quickie" with any given house fly if you wanted to. A familiar feeling came along to queue an egg laying, so you did your own business and went to look for Samantha.
You soon found her, but you found she was around a large group of flies. She was currently in the middle of mating with a female fly, counter to your own experience. The female fly was robotically standing, making adjustments every once in awhile, while Samantha was doing a frenzied humping. At some point she made a very-un-fly-like wave to you to signal she noticed your presence, but continued her act. Due to the large group of flies, you soon had some males interested in you as well. Suddenly you felt a familiar feeling in your mind.
(Jacob...this...is...amazing. Can...have...sex...all...day. You...should...join...in.) You hear from Samantha's telepathy. It still wasn't a superb way to communicate but there was no better way for her to offer you to join a buggy orgy. Figuring Samantha was going to be at it for a bit, and good part of "For science" and self-interest, you turned your back towards male fly and did the deal.
You and Samantha went at it with various flies for hours. It was good for you, but great for Samantha. For her she could do plenty to make the experience more creative and pleasurable, while the male flies pretty much all did their business the same way. Heck, at one point you gave a "blowjob" to Samantha while you were in the middle of being mounted. After taking it in more, you mentioned if this felt like "cheating" to Samantha. After some dialogue, you felt that feral sex with the flies was just that, and ultimately you had feelings for each other. You also got some side experience of regular house fly behavior, including when they would get grabby. Both you and Samantha were large and strong as flies went, but dealing with a large amount of other insects could be its own issue.
Soon more time passed...