Here's an example of some voice clips you could use:
<a href="https://www.youtube.com/watch?v=0bXTSDF8wDU" rel="nofollow noopener" target="_blank">https://www.youtube.com/watch?v=0bXTSDF8wDU</a>
Tons of grunts and groans without any background noise. There's even choking noises at 1:28. I think using clips like these would really make your video sound much nicer.