Good trick.

Bet a girl £1/$1 you can make her tits move without touching them, then stand and stare at them, [good so far!]. Pretend to concentrate hard on them, wave your hands around like you're casting a spell, and then have a quick feel of her boobs. They are delighted [momentarily, till they realise they've been fooled] that they won the bet, and you are delighted too, 'cos £1/$1 is a cheap price to pay for a quick feel.
Giok

BTW, run like buggery after you've grabbed them!