I always thought it was "in his pants" :)

but the other thing I wanted to mention, when my dad was in palliative care and dying from kidney failure (this is 9 years ago now) and he lost his speech, my mom who sat with him the last time recalled that he was humming this song.

(I should point out that I always believed my dad was an atheist since he was a member of the Communist Party in Czechoslovakia - but when he took the time to write his memoirs we found out that he rebelled against his father (who also happened to be a long time member of the Communist Party) as a teenager by going to church on a regular basis. This would have been just after WWII in the late 40s and the Church did provide a lot of activities for young people in sports, music etc. I suppose he later distanced himself from that as he joined the party and the Czech military. But it is interesting that he hummed this song in his last moments.

Petr