i have 2 oscar fish one 4" and the other 3" the big seems to be bulling the smaller so the small hides all the time and only comes out when its time to eat,but i have also noticed that the big waits for it to come out how do i no if the big one wants a hump..lol

What size tank do you have the 2 oscars in. as the 2 fish are still very small there is no chance they are sexually active so definitely don't want to "hump". most likely they are just trying to sort out who's the boss. as long as no real damage isn't occurring they should sort it out between them and settle down, if fighting gets to the point that damage is causing the fish distress then you may need to remove one.

the 2 oscar are in a 200 litre tank

your tanks no where near large enough for 2 oscars. ok so they are small at the moment but you are in need of a much larger tank ASAP. this is most likely why the bulling has start, but may not be the only reason.your going to need around 100G plus to keep 2 large fish like oscars.
www.oscarfishlover.com/helpful-articles/oscars-need-big-tanks

exactly what marcus says...

aggreed, good enough for now, upgrade needed soon.
Or a rehoming of one fish...
I'd go for the upgrade.