Someone else is going to explain it in full. I'll just see if I can get this thing started. In some ways it works like another gender, or perhaps, along with masculine animate and masculine inanimate, it would better be described as a sub-gender.
I know that it makes a difference in certain cases - genitive and accusitive are the same in masculine virile, whereas they are not in masculine inanimate, with animate being somewhere in between by having adjectives the same as masculine animate and nouns the same as masculine inanimate, blah blah blah. Hopefully I haven't gone wrong already.
It also makes changes in verbs in the participle which forms the past and imperfective future tenses. Then there are some adverbial gubbins I don't understand or something like that. Well, I did say I don't understand.
My first question, though, is: in a mixed group - men and women, do things revert to the non-virile form?
A man and a woman:
I'm prepared to put two of my hard-earnt groszes on the first one, but I'm always prepared to find out that I'm wrong.
Okay, so that was better than nothing. Thanks PolishGirl.
These Lazy Men Are Eating Cakes
Apparently, adjectives, numbers and numerical expressions have masculine virile forms. These adjectives seem only to turn up in the plural. It looks like some sort of softening of the final consonant that marks the change of an adjective from masculine plural to masculine virile plural.
Ten leniwy pan je ciasto
Ci leniwi panowie jedzą ciasta
That's a nice simple one because -wy softens to -wi. Some are than simple, but not all of them. But now, having received confirmation from a wonderful PF poster about just how masculine this particular kind of plural has to be, we would also just talk about people generally (assuming there to be a mixed sex group)
Ci leniwi ludzie jedzą ciasta
But animals are not included
Te leniwe osły jedzą marchwie
Unless those animals are actually people.
Ci leniwi osły jedzą buty.
I'm just going to leave with a few examples of nominative plural adjectives in masculine virile, then for all other genders, which thankfully, are all the same. Then I will hope that someone else may shed a little more light on the subject while I sleep and dream about carrot cake. I've written more than enough that I still don't really understand. Corrections please, where necessary.
najlepsi - najlepsze ... best
najgorsi - najgorsze ... worst
starzy - stare ... old
młodzi - młode ... young
tacy - taki ... such
polscy - polskie ... Polish
drodzy - drogie ... dear (as in "Moi drodzy" at the start of a letter)
mali - małe ... small
duzi - duże ... large
którzy - które ... which (as in "Ci ludzie, którzy lubią ryby" - I don't know why I thought of that)
dobrzy - dobre ... good
źli - złe ... bad
masculine virile plural adjectives are one thing (own endings) and all the rest are the other type, this division also rules the past tense endings (the same pattern) (you can in a way see the past tense as adjective like (it had once been a participle and participles in Polish (most of them) share declination features with adjectives)) (there are some participles that share features with adverbs - imiesłowy przysłówkowe)
I mean all the rest of adjectives in plural
(so it looks like horses are all mares ;) te konie like te kobiety, te delfiny, te kotlety, te okna, te gacie, te dzieci vs ci faceci, ci sąsiedzi, ci gamonie, ci piłkarze)
konie były, kobiety były, dzieci były, kotlety były vs Niemcy byli
spokojne konie, spokojne kobiety, spokojne dzieci, spokojne kotlety vs spokojni Polacy :)