The lemonade

General Information
When drinked, the Heavy from tf2 Voice will say "Hmm, is nice.". After which, your character will appear shocked, when the *Realization* Text appears.

Then you drop your "Lemonade" cup, and die.

It is most likelly a TF2 reference to the sniper's "Jarate"

Location
The lemonade is in two places one in the lemonade stand where the shotgun, Which is the Tools. Yeah. Stand, aka: Lemonade Stand. The other one being the AWP Shack.