It wasn't as obvious or frequent as Undyne. Just the occasional 'damns' here or there.
Huh, I went to check, but I can't seem to find any instances of me making Twilight actually 'curse' >3> the closest I found were Crap, Screw it, and Freaking... then again, maybe I missed a post in my search.
Undyne's were really mostly me letting my brain run off thinking about what one might say in certain moments if they were exceedingly experienced or driven by anime like stuff... I mean, seriously, That was 'tame' compared to some of the anime's I've seen. Keep in mind, I'm referring to the 'originals' of some series, not the censored and cleaned up American rehashes we get after the FCC or whoever gets done butchering what they were originally made to be.
I 'still' remember when Vegeta got his arm blown off/busted to hell and just went 'Dah-nit'! I had actually 'seen' that scene a long time before uncensored, there used to be a lot more blood and cursing in DBZ XD But seriously! My suspension of disbelieve refuses to wrap itself about someone being severely injured and stopping at 'darnit', unless maybe they've never been considerably exposed to vulgar language before and 'literally' don't know words that one expects to express such unimaginable pain.
Heh, just imagine if I'd used 'The Saint's boss' instead... He'd ruin everyone's innocence before day three! XD
Edit:
I thought of something too, and I'm not exactly 'arguing' so much as generally pontificating on the subject and providing what I've thought of to see if it might be of interest.
Twilight, being from a vastly different culture from ours that may well not use the same words we use in the same way [God, It's still weird if someone uses 'buck' instead of 'fuck' in real life, I mean... seriously XD]
For her 'damn' would just be a shorter version of Damnation, and given the intellectual element that is ever present, simple use of certain words might have less meaning than the intent or tone behind them.
I try to experiment with the cultural differences whenever I can... or, when I can remember at least, Wish I had a better memory sometimes. I could almost imagine her innocently asking someone 'what's a fuck?' XD or 'Why would calling someone a female dog be an 'insult'?'...
'bitch' could literally be a standard gender identifier for a female of a canine species where she's from. Hell, It's only a real 'insult' in our culture because, aside from the obvious element of intent to insult someone, so many of us consider a dog to be inferior to humanity as an animal, and thus making calling someone a dog an insult.
On a side note... I have as much a habit of wandering off on long winded TAngents as Twilight does XD