to have a bun in the oven

(idiomatic, colloquial) to be stacked, to have big breasts

(informal) to give up trying to guess something, e.g. the answer to a riddle

bit by bit, gradually

(idiomatic) in keeping with (progressively, in sequence)

same difference, six of one, half a dozen of the other

(informal) to have bats in one's belfry

to bet one's boots that, to bet one's bottom dollar that

to the letter, literally

(idiomatic) to roll one's eyes