I do not rinse out the ACV after I use it, and it is the last thing I do to my hair during a wash.
Robotxcore, there's no "verdict" on whether to ACV before or after conditioner. Different strokes for different folks. I have always ACV'd after conditioner, and I believe Allandra has always done it before. And you'll find lots of people doing either. Only you can be the judge of what works for you.
I ACV at the end because it makes sense to me to close my hair's cuticle and leave my hair in a pH that is more normal ie acidic. Closed cuticles mean less tangling, less likelihood of the cuticle to be torn off by friction between the strands, and it gives a better sheen to my hair than if the cuticle is left open.