The noun phrase 'King Horse' would ordinarily be taken to mean 'King of the Horses', much as in 'The Lion King'. In context — 'between tenderness and brute force' — and the liner notes already quoted here, it seems as though Costello is suggesting that the men he's observing have some of the pathos of adolescent love (‘never seen’); the male in the last verse doesn’t use brute force, but asks (pleadingly?) ‘Will you please?’
So in context, it sounds to me as though this reflects a crowd of late adolescent boy-men at a cheap strip club (‘Teased up by a strip cartoon’, in the kind of punning word order reversal Costello loves), who are self-representing as stallions, but who in fact are just colts.
The noun phrase 'King Horse' would ordinarily be taken to mean 'King of the Horses', much as in 'The Lion King'. In context — 'between tenderness and brute force' — and the liner notes already quoted here, it seems as though Costello is suggesting that the men he's observing have some of the pathos of adolescent love (‘never seen’); the male in the last verse doesn’t use brute force, but asks (pleadingly?) ‘Will you please?’ So in context, it sounds to me as though this reflects a crowd of late adolescent boy-men at a cheap strip club (‘Teased up by a strip cartoon’, in the kind of punning word order reversal Costello loves), who are self-representing as stallions, but who in fact are just colts.