We do a modified version of this which involves no downing drinks, just purely looking a tit. Get a pack of condoms, preferably dodgy flourescent ones or summat, and proceed to stick them on your mates shoulder and see how long it takes them to realise.
We spent half the night in tiger tiger with my mate having one on his shoulder, everyone was wanting a pic with him but he couldn't figure out why!
Instead of drinking games I ended up dressing my mate up in a one piece swimsuit with some goggles and a snorkle with a funnel on the end which was used for downing pints, was well hard to dunk a full pint but had a proper laugh trying.
Was especially funny when one lad who everyone loves to wind up put it on to down his bottle and everyones eyes lit up, not sure how many drinks we got in there but it was a fair few, lager, cider, g and t, etc.....