bog in

He closed the door and motioned them to a tray. `Bog in, it's all on the house.'

The soldiers swept into the trench with a cheer! Some of the Turks remained to argue the point with the Australians, but the bulk of them ran squealing, for fear of being stuck, like pigs, to the second trench. Those Turks who stopped to argue, argue no more. `Advance, Australia!' resounded through the bushes. `Into the cows! Bog in, boys, bog in!'

North of the Alps, you can have heat and sun--but some summers (if you go far enough north) you can also be bogged in by rain and enough chill that you have to go out and buy wool hats.