A blunt that is either a) dipped in dxm and smoked, or, for a better effect and easier smoking, b) drizzled with robo or other dxm-containing syrup before it is smoked. If using the second method, one would normally place it in the freezer for about 15 minutes, or until the blunt is no longer too wet to smoke. A person who smokes a robo-blunt will almost certainly trip balls.
"We got that tussin, them blunts is dipped three times"
"Man, I smoked a robo-blunt at that party last weekend, and suddenly I was having a fucking teaparty with a bunch of garden gnomes and midgets"