myriaddigits
@mra
I'm not sure he could've picked a worse choice of words.

Jono
Improper words but the meaning is still valid.

Kid Cthulhu
Whoa, talk about berserk buttons!
Ash SMASH!

That Guy
Two choices here:
1: Sam: "Wait... You're not saying..." *facepalm* "Oh. My. God."
2: They actually kiss.
I give it a 70/30 probability in favor of 1.

Wally
Oh dear, it was a kiss that started this mess.

Wally
...now that the obvious has been addressed; Why does Ash react so violently to a simple yes or no question? It isn't as if she was boy wearing perfume. Ash is a girl and it isn't that strange for young girl to wear a nice scent, especially for a special event like a wedding.

Rick
I love Sam's ninja reflexes calmly catching Ash's arm.

Toothless Gus
@Wally, At her age? Not really. Given her feelings regarding make up and dresses, it's not really surprising.

wally
@Toothless Gus: Not in my experience... my wife and I raised 2 daughters, four years apart (with a son in between). There was no problem getting either of the girls into dresses, makeup, and perfume from pre school on. We had more of a time trying to get them to dress down, wear jeans and such for play. Of course in Australia, things might be different than here in The USA.

Charidan
@Wally
For the same reasons Ash isn't wearing a dress. And for that matter, why Charlie might be equally upset to get caught in girl perfume. "Girl" things have a lot of gender constructs and stereotypes associated with them that many girls nowadays want nothing to do with.
In other words, that definition of "girl things" is getting outdated and girls find it offensive/demeaning.

Charidan
(Ninja'd!)
Upbringing has a lot to do with it, and this certainly isn't a universal thing.
The short answer is "tomboy". Ash is a tomboy, which is basically defined as girls who reject girl things and do boy things. The word has been around since the 1550s, and the concept is probably much older.
You could argue whether tomboys are trying to maneuver social stereotypes and gender roles to be seen as higher status or just don't care about outside pressure and are doing their own thing, but that's kind of a moot point because they exist and act like this. The grander societal implications are a little out of scope of this comic or the question in this thread.

DMAN
Just kiss. :^}

T
@ Wally: Think about it. Ash is reacting like any masculine girl (or or possibly FTM) who was accused of something girly i.e. like many masculine boys would. It's a threat to one's identity.

Future Self Wingman!
To the Rescue!
Hooking his past self up to better his future.

0xf10e
@That Guy, I go with option 2:
Ash first forces a kiss upon Charlie and then drags him to Kate to put make up on him ^^

Jack Jack
@Wally: Charidan answered your question, actually. Ash doesn't want to associate with femininity in many cases, ie dresses, make up, much less be seen by someone close to her in such things. She'd feel like it was ruining her image. She was already really angry with Charlie, so the question just pushed her a little farther over the edge.

Jeudi Violist
Oh! I get it!
They're thinking he said "It was just a kiss and some make-up" and so now they're having a staring contest to determine who it was that told him.