Just a humorous idiom! The usual expression is man a man i...:
- Man a man i ni fynd nawr (We may as well go now)
- Man a man i Siôn ymadael yn gynnar ddoe. (Siôn might as well have left early yesterday)
Is a literal translation possible? I'm have no idea how it could come to mean that.
The man here translates as 'a place/spot'. The whole expression man a man i... is an idiom - it makes no real sense in a word-for-word translation, at least in the modern language.