Vinegar??? Ouch!
It's completely unnecessary, unless maybe if prescribed by the doc for certain conditions?
The internal area is basically self-cleaning, and using anything to wash will unbalance the natural pH and internal flora and might lead to infections.
They used to sell douche bags and douche kits in the chemist. It's just that 2 weeks before my period, I smell like a feral animal and my partner's mum's dogs get very excited and try to bury their heads' between my legs.