wing it

wing it (to improvise, to do something (difficult) without proper preparation or time to rehearse) — импровизировать, действовать / придумывать что-л. по ходу событий; ≅ нести, говорить отсебятину

You tell people that you’re winging it (that you’re improvising), so that they won’t expect too much from you, or so that they will be more forgiving if you make a mistake.

Example 1: Sorry if I seem a bit disorganized, I’m totally winging it. (BAE)

Example 2: I hadn't had time to prepare the talk so I just had to wing it. (thefreedictionary.com)

Related vocabulary:

[play it by ear]
[off the cuff]
[at the drop of a hat]
[с ходу]
[навскидку]

The idiom has nothing to do with wings with feathers. This expression might also be thought to be derived from 'on a wing and a prayer', which alludes to aircraft that return to base more in hope than expectation. That's not the origin either and, if anything, the derivation is the other way about. 'Winging it' is a theatrical expression which refers to impromptu performances that given by actors who had hurriedly learned their lines while waiting in the wings and then received prompts from there. (phrases.org.uk)