[sir stefan]

This dare can be a lttile difficult to execute alone.
The wide-streched position will make it an heroic dare.
Lots of fun for your friend(s) to watch

get yourself 2 alligator-clamps (check google if you dont know what i mean)
attach a twine to each of them.
lead the twines to some "ring"at the ceiling (you need to figure out how/where).

Than:
Tie each twine to a 2.5kg weight such that If the clamps are at breast-level, the weights are also at breast-level (you need help here)

Now:
be naked
get clamps on nips
each hand to hold a weight
arms stretched to the side

keep position for 10minutes

I would guess your muscles will slowly giveup and the weights will start pulling your nips