Normal conversation: Using one of the standard emotes found under 'help emotes' does not require anything before it. Custom emotes (such as Player jumps around), would be done in the following:
:jumps around. (no spaces before the ':' )

Communication channels:
To emote on chat channel, use the following syntax:
chat ;emote
Example: 'chat ;laugh' will make you laugh on chat channel.

For a list of the set emotes, use the following syntax:
help feelings
A list of adverbs can be found under help adverbs.
These can be added to the syntax for the emotes, to help liven up things.

See also: communication