all my eye (and Betty Martin)

Nonsense talk. The origin of this phrase is disputed, but it may have originated with a sailor whose retelling of a beggar's (misheard) words was regarded as nonsense. Oh please, she's not rich. Any talk of wealth is all my eye and Betty Martin. If he says he's good at tennis, it's all my eye—he's terribly uncoordinated on the court. Philip talks like he's some suave ladies' man, but, believe me, it's all my eye and Betty Martin.

like a martin to his/its gourd

dated, colloquial A reference to the purple martin, a type of swallow that often nest in hollowed-out gourds provided by humans. Primarily heard in US.

1. Very fast in a straight line. He stepped in the door and walked over to the bar like a martin to his gourd.

2. Quickly, directly, and intuitively. I wasn't sure Sarah would be cut out for carpentry, but she took to it like a martin to its gourd.