"Bungalow Legs" means that you will lose the ability to go upstairs! I can see what they mean... brilliant!
In a similar way, we should try not to neglect our Welsh skills, whatever stage they are at! Because there's your warning ... stop doing things for a while and you might well get the Welsh-learners equivalent of "Bungalow Legs" and find yourself slipping backwards horribly down the grisiau! Ouch.
On that cheerful note I will give you some top music with your own, your very own GZM and Thema O Cartref ... oh, I'm back from my Welsh gwib by the way ... loads to talk about there !