Get a roll of parcel tape, the thin crinkly plastic kind, and wrap each tit from the base to just short of the nip. Pull and twist the tape in different directions as you wrap, so you have patches of skin stretched different ways and scratchy creases digging in. Once your tits are taped till they look like Madonna conical bra cups, run a bit of tape from the top of each up to the shoulder so they stand out straight from your chest, then put a thin teeshirt on and go shopping or to work.

Between the discomfort of the wrapping, which isn't big but never stops and gets worse the more you move, and the humiliation of going around looking as if you just had them massively enlarged, you'll find this is worse than it sounds.