Birthday Present for Shiro

 is a shard in.

Transcript
Happy birthday you crazy motherfucker! Sending you our best wishes aaaaaand a little present :D You've got glitter (DONT [sic] do it all in one go) and other goodies. Hope your party fucking SLAPS. We'll try to drop by, but can't promise anything. They're making us do overtime at the lab to pump out this glitter shit. Demand's off the goddamn charts. Try it and you'll know why ;) All the best from your chooms on Rovinj Street!

Location
This shard can be found in the Kabuki slums visited during Big in Japan. In the southern part of the slums, there are two houses with blue roofs. Check the house that's closer to the river. The shard is inside a yellow container in that house.