Fistbump was at a disadvantage in appealing to me from the very start: if each fic were a meal, underage and incestual content would be the parts I'd eat around. However, what I really like is believable story-telling with genuine expressions from the characters therein. And Fistbump has all that in spades. In fact, it accomplishes something particularly special by managing to use its taboo material to support and enhance the story. Instead of being in service of titulation or shock value, Fistbump not only justifies the inclusion of that content but would be a lesser story without it. It's glorious and very impressive.
As though that weren't enough, this story is well-written and riddled with sincerity. It does a good job capturing the feel of the canonical material so that it actually reads like something from the GF setting (as opposed to being a story with characters who happen to be named "Dipper" and "Mabel"). These are all qualities that are hard to find in amateur writing, let alone in explicit fanfics, which makes me all the happier I stumbled across this story. Edward_or_Ford, you've written something great here and I thank you for making it.
All right, this is a pretty excellent story. A bit longer than I usually will read (well, actually listen to) but it was worth it. The slow build-up and deep plunges into the kids' feelings and reactions was pretty good. Maybe a few times I felt some lines, mainly the extra explanations that were easily implied from the context, could have been left out. That would have shortened things a little but got across everything you wanted to express. (Not that I haven't done the same thing, of course. :))
Opening was great, especially the blackmail bit to get Stan to agree. The ideas flowed very naturally and believably. The exposition there was good, though it wouldn't have lost anything if you left out the full itinerary since that all gets across well enough in the moment. Still, it was a pretty great plan and definitely fit with what young teens would want to do.
I felt the kids were in-character most if not all of the time. Dipper crying at the museum was a bit of a shock, but in the context of his emotional rollercoaster of a morning it works. Mabel's process was a lot of fun too, and I'm glad that Dipper heard everything. The innocent-enough day itself was entertaining, and the not-so-innocent night was quite hot... after some really sweet and deep soul searching. Also, Dipper's method of calming Mabel after she fell in the water was genius and perfect.
Again, delicious work on all of the sexy scenes, from masturbation to exploration, and then especially full consummation. I'm glad they got to have a lot of fun afterwards, even if Stan caught on and (rightly) put a stop to it. While it's not as happy an ending I might have wanted it didn't end on a down note by any stretch. It left open possibilities (which I'll see when I get to "Fistbump 2." :) )
As for mechanics and stuff I converted the story to speech and listened instead, which makes some things stand out quite a bit: there were a handful of typos, missed or extra words and the like. Nothing serious or enough to throw the reader. If you'd like the audio files I'll put them on Mega and send you the links via a forum PM... or you can share them with everyone if you like.
Anyway, thanks again for quite a wonderful story, from lead-up, innocent birthday stuff, and then of course the wonderful lovemaking/boinking that ensued.
I do hope that you make a sequel.