I.e.
exclamation:
*George walks into a crowded area seeking attention* "SHROOMARANG!" whole room turns to look at George; mothers escort children away from George.

quizzical:
Jill: "George, answer me honestly...do you like me?"
George: "Shroomarang?" *runs away* *Jill is very confused*

Ice Breaker:
*George is at a company party in a small room, many people. He releases gas loudly, all noise ceases*
George: "Shroomarang!" *party returns to normal*

Annoyance:
*George is conversing with a friend on an Instant Messenger*
Georgio114: shroomarang shroomarang shroomarang shroomarang
megame2b: STFU
Gorgio114: shroomarang =)

Note:
There are many uses for "Shroomarang"....

How do you Shroomarang?