I'm prolly in an earlier stage with my old geezer's hygiene. We got rid of bath years ago (2 x hip replacements for me plus his 1 x hip and 1 x knee meant over bath shower simply wasn't a good deal) but I just say something like ..... "Shower's going on - you gonna get in or waste your electricity?" or "C'mon mate, let's freshen up, shall we?" or "Let's use that new shower cream, eh?" and if all else fails then "Phew - you are REALLY NOT NICE Mr Stinky-Poohs" .... It depends on the day, weather, mood (mine and his) but I have even threatened to put him in the garden and hose him down. I'm sure my olfactory nerves have been fried away but hey-ho .... smelly is better than the alternative. Maybe.