As a 'male' actor I ticked my agent costume box- 'does drag'. Is this 'wear a dress' or is it makeup/shiny dress/big hair stylised thing?

I would imagine it means you can provide a suitable costume and perform in drag. If you can't, ask the agency how to edit your form and leave the box blank.

I would count on the whole thing.

Nobody should ever tick a box that they don't understand.

A very, very basic rule of common sense.

What do you mean by putting 'male' in your question in quotes? Are you not really male?

I've never heard of a 'costume box' on any agent's forms.

If this is a genuine agent, you can just phone and ask what it means.

If you're trying to tell him that you're a drag artist, say so.

But as it sounds like you don't know what drag is, I suspect that you do not. A man pulling on a dress does not make him a drag artist!

If you don't know, why did you tick the box? Muppet.

it means you will wear ladies clothes, generally makeup and hair go with the whole package

Just to make sure, you should wear a dress as well as do the makeup/shiny dress/big hair stylised thing. Top it all of with a pair of Doc Martens boots. Go the whole hog.