I cannot instinctively tell left from right. I can work it out, either by little physical checks such as "Left hand for frets and right for picking", or by feeling with my thumb the writer's bump on my right middle finger. (My mum blesses herself with her right hand and I catch her doing that to confirm whether she's going right or left.)Normally it doesn't matter too much ... it only takes a second or two to work it out. I'm taking driving lessons and I've been able to intellectualise the left/right thing another way. We drive on the left and so when the instructor says turn left, I think "Easy." When he says turn right I clench my buttocks and prepare for a difficult manoeuvre.
Where it really matters is when I'm co-piloting for my wife and we approach a junction and I say "Left here". She turns left. "Shit, I mean right!" Has been the cause of a fair number of rows.
Funny that I don't have east-west confusion to the same extent!