Can I use an emulsifier in my buttercream icing so it doesn't melt from the heat of my hand while decorating? Any suggestions of types or where to purchase?

I use the Princess one and it's only for taste and not needing so much extracts. Have no idea about the hand heat.

Princess is a flavoring It is an emulsion, meaning that it was made with some sort of emulsifier so that water and fat could combine, but there's not enough emulsifier in it to do what the OP is talking about.

We already use emulsifiers in our buttercream, or lots of us do anyhow If you make Wilton's buttercream recipe with the meringue powder added to it, it has gum arabic which is an emulsifier. Personally, I use Indydebi's buttercream with the Dream Whip powder in it. Dream Whip has a couple of different emulsifiers in it. When you use it, it keeps the milk and the shortening from separating, so you don't get the greasy mouth-feel or the speckled look that buttercream will sometimes develop.

if you will use sharon zambit's recipe..she shows it on youtube.. she uses hi-ratio shortening.. no need for anything else.. very stable in hot weather,etc.. taste great.. no gritty feeling using the dream whip.. no greasy mouth feeling.. try it ..you will love it.. hth

Hi-ratio shortening is an emulsified shortening. [You can use it by itself, or in varying proportions with butter to acheive a better taste/mouth-feel.]