He's smirking anyway, long before she adds the 'on a horse' caveat. Predictably.

'Midnight ridin's a favourite of mine too.'

Beat.

'Not on a horse.'

Because there was obviously going to be some doubt.

'Alrigh' then...' shit, he's always been useless at this sort of thing. He's more likely to come up with something lewd, or something too searching, that'll spoil the mood, '...favourite thing about Milliways, apart from all the weirdos you hang aroun' with.'