rustling, thrill, tumult, quiver, rustle, murmur, purl, babble, whisper, mutter,
We pushed off from the shore and glided into the heart of the river - around us just the sound of the wind soughing in the reeds and the lapping of water against the hull.
4π 1π
When you switch the letters S and R in the first word, sough becomes rough.
Then, when you do the same for the second word, Rex becomes Sex.
So, swapping the letters in sough Rex gives you rough Sex.