Yeah there's only one thing you are going to get if you rub olive oil on your breasts: Oily breasts. You might even ruin your clothes if you get any of the oil on them...
Maybe this idea started because oil has high fat levels, but your body doesn't absorb fat that way. Did a guy tell you this? Maybe he just get's off on girls rubbing their boobs and tried to trick you into it..
If you want bigger breasts, there are only 5 things that will help:
- Boob job
- Getting fat
- Getting pregnant (kind of related to #2)
- Push-up bras
- Hormone changes when you're on your period
Rubbing food items on your boobs does not help them grow in any way. Put the oil down!