Yes, you can. (Well, only if you're a child arguing with your siblings about a favoured position in the family car. Otherwise, no. Adults don't talk like this). Following on from Bramwell and John's replies: Shotgun ( also 'calling shotgun') is a very American expression. I don't think it's used outside the US. 'Dibs' seems to be universal. It's known in both the US and the UK, and probably elsewhere also. We also have the expression 'First dibs (on something)', if there's an issue of choosing the most favoured option amongst several. One British expression which may not be known elsewhere is 'Bags' or 'Bags I' or even 'Bagsy'. For example, "Bags I go first on the slide!" or "Mum! It's not fair! Jack always bags the front seat". That's the expression I'm most familiar with. I'm guessing it comes from the idea of shooting or stealing something ( a rabbit or game bird, for example) and claiming it as your own by popping it into your bag. Anyone know if 'Bags' is also used in Aus/NZ? It's been going for quite a few generations, so it may well have spread to the Antipodes.

"dibs is British" and used by Children to make a first claim on something it is a little old fashioned sometimes you will hear "dibsy". Riding shotgun is American for taking the point an up front forward position to protect something a convoy of troops or settlers travelling in coaches across America in the early days of America being colonised. I don't think we use that term to claim a front passenger seat in the UK Taking or claiming 'first dibs' on something may possibly date back to claiming the first dib into food

Yes, it would be natural and correct, but very informal. 'Dibs' as a way of staking a claim is normally used by children, but is sometimes used by adults. I have never heard 'shotgun ' used in this way. Or are you using 'shotgun' to refer to the front seat (also known as the passenger seat)? If so this is not a usage that is used in British English, but does sound like it might be an American usage

If you previously referred to 'the urban dictionary' that dictionary should not be taken seriously, it allows anybody to type in any old nonsense they want without any sort of academic references. Shotgun is not used to claim a front passenger seat in a vehicle as suggested by 'the urban dictinary'. And it seems 'dibs' may originally be American at least at one time in history from a children's game; although there are other earlier references to a division or first share of something In English English. "bags I" or "bagsy" which I have also heard from children seems to originate from putting a catch into a bag. As Su.Ki suggests and I always assumed was it's origin. "Bags I" or "bagsy" is British. Dibs may be one of those where we have lost the original meaning and now like many things there is confusion and disagreement on whether it is American or English. A which came first scenario.