Chat tricks. How do you do it?

I have recently seen on multiple occasion of a player typing something in chat and have it come out in yellow italicized text starting with the summoner own name. ( example: CaptainPeeWee is awesome) I've asked how to do it and yet no one will tell me. Could someone please teach me how to do it? I have typed "/me" and found out it came out as my own summoner name.