[Vocabulary] lie on one's feet

[constantinusphilo]

If there's one thing I'm good at, it's lying on my feet. It's sort of a gift I have.
The Secret History by Dona Tartt
I do not understand the phrase in bold.

 

[Tarheel]

It means lying in the sense of deceiving people, trying to get them to believe something that isn't true.

 

[Skrej]

More specifically, it means she has the ability to concoct a believable lie at a moment's notice, without time to prepare.

It's a variation of the phrase 'think on one's feet', meaning to make decisions quickly or give answers without hesitation.

You can substitute many different verbs with the same idea of doing it quickly or without hesitation. It can also imply a sense of adaptability.