I have a question about Little Miss Sunshine.

I love this film, and I've watched it about 5 times within the past 24 hours.

After blasting the volume, I am FAIRLY SURE that I hear people having sex during the scene when the Hoover family pushes the bus after the policeman drives away.

I followed the sound, and it matches when the family is getting out of the car and walking behind the bus. When they start pushing, not only does the sound not match any of the characters, it actually sounds like people having intercourse.

Was this an artistic choice by the sound mixer for the film? Like, a clever addition following the porno magazine scene? Were intercourse sounds actually dubbed in, or am I just crazy? Have I been watching this movie for too long?

Has anyone noticed the same thing?

I adore this movie for all its cinematic aspects, but now I'm very curious/confused/. I would contact the sound mixer (Steven A. Morrow), but I have no idea how.