Question: What does テラス means in the context of declining an invitation, like below?

> 
> うううううう！！いきたい！けどその時間帯もろに仕事だ：：：またやって！！テラスーーーーー
> 
> 
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I guess it is slang?

I am familiar with テラワロス but it seems different in both spelling and context.

More context: Public comment sent on a night-time birthday event page on a social network. テラス is not her nickname.

Answer: 
So far the only viable explanation I can think of is that テラス is a contracted form of テラワロス.

* [ニコニコ[百科]{ひゃっか} entry for テラス](http://dic.nicovideo.jp/a/%E3%83%86%E3%83%A9%E3%82%B9) defines it as: `3. テラワロスの略`
	+ 3rd sense: Contraction of "terawarosu"
* [a 2ch.net post](http://2chnull.info/r/train/1273323743/901-1000) says:`「法テラス」（ﾃﾗﾜﾛｽじゃないぞｗ）`
	+ "Law-terrace" (and no, it's not "terawarosu" lol)
* [a blog post](http://blog.kanjosen.com/?eid=1006137) writes: `「針テラス（テラワロスではない。2ちゃんの見過ぎ）」`
	+ "[Hari Tea-time Resort Station](http://hari-trs.com/haritrs.html) (to 2ch addicts: it's not "terawarosu")"

As to why you'd want to "roll on the floor laughing" in the context of declining an invitation, I don't have a definitive answer, but maybe one of these:

* She's laughing at the unexpected coincidence of the event and her work.
* She's laughing at herself for having to work when everyone else is able to attend the event. Perhaps the time of the event is normally considered overtime?
* She's softening the request to hold another event for her by adding a laugh.
I'm Japanese, but I've never heard Japanese people using テラス. That's not even slang. I don't understand its meaning.