Awesome. Definitely looking forward to more. This small chapter was nice, but it was as you said, small. There wasn't much happening in this chapter, but hopefully you'll write in a few sex scenes in the next chapter.

As for ideas, you could introduce Alex to Fey(which I'm pretty sure you plan to do) and have Fey surprise Alex by invading her body when she's sleeping or distracted. Fey could clamber through her body and mess with her organs and what not. You could even mix brain play into this by having Fey travel to Alex's brain through her ear or something while using "fairy magic" as an excuse to why none of this causes any serious harm. With Fey being so small, you could have her go up Alex's urethra and into her bladder; you could have her squeeze through her fallopian tubes and to her ovaries, maybe even have her travel to Alex's heart through her nipples or perhaps mix in some form of navel penetration.

On the other hand, you could have Fey be attacked by some small creature of your choosing and have her get caught caught by it. The animal could(if it was an earthworm or baby snake or something similar) try and enter one of her holes and take up residence inside her for a time. You could expand this part by having it be active while in her messing with her organs and such.

Another one is having Fey get stretched so much that her entire reproductive system turns inside out and not just prolapsed but completely inverted with her ovaries having been pulled out through her tubes. A variation of this could be Fey's vagina getting stretched so taughtly around Tim's fingers that when she gets yanked off suddenly, instead of coming off Tim's fingers, her body could come off, but her entire repreproductive system could be yanked out cleanly, ovaries and all.

Finally, you could have Fey accidentally get caught in the vacuum and be partially sucked up with her upper chest and arms being left out. A air tight seal could be formed and the pressure build up could start sucking her intestines out until it sucks up her entire digestive tract, including her esophagus.

Also, if yoh or anyone reading this has a pdf of Berty's Watch, I'd be appreciative if you could upload it.