Three Pebbles in English Language Beach

"c'mon" = come on = used to try to suggest that someone change an opinion that is unreasonable or that the person joins you

"You like eating raw meat? Come on! That's nasty! "

"Come on, let's go to the bar"

I have no idea about "dsn".

"here-on-in" looks like a mistake to me, but the meaning is clear. It's "from now on".

Festival is based on the same root as "party" in many languages. It can be described as a large culture-wide party ot simply a public party.

I've guessed "here-in-on" as what you indicated, but it seems not a mispelling. The poster of "here-in-on" is from Ontario, Canada.
I've gotten inspired by your explanation upon "festival".
Thank you Craven de Kere.

Here-on-in is very much a canadian saying. Craven is right, it does mean from now on.

Wow, now we found Canadian English is different to American/British English.

In this case it's actually the opposite, Americans are more likely to use the expression "from here on out". out vs in

I think dsn will be an abbreviation of somebody's name.

It's difficult to try to learn idiomatic speech by writing about it....and it constantly changes....but "aw, c'mon" could be said to be the same as "get real" or even "hello?"

See what I mean? Watch more television!

oristarA, your description of "three pebbles..." really made me smile! That's an example of excellent use of the English language!

I'd guess "dsn" is just a typographical error. The letter "s" is right next to the letter "a" on the keyboard. Maybe it was supposed to have been "dan" - a common male given name.