This is the 13523rd most frequent Polish word.
piana
Foam or froth.
Here, 'piana' refers to foam, specifically, bubbles formed as a layer on a liquid.
Na powierzchni wanny unosiła się biała piana.
On the surface of the bathtub, white foam was floating.
In this metaphorical usage, 'piana' evokes an image of emotional intensity, referring to an arousal or excitement.
Perkusista grał na perkusji z taką energią, że moja piana biła jak szalona.
The drummer played with such energy that my excitement was overflowing.
'Piana' here means a mass of foam made of a specific substance, in this case, whipped egg whites used in cooking.