clear my nether throat

fart

Mark Twain, "1601"

Sr W.--Most gracious maisty, 'twas I that did it, but indeed it was so poor and frail a note, compared with such as I am wont to furnish, yt in sooth I was ashamed to call the weakling mine in so august a presence.
It was nothing--less than nothing, madam--

I did it but to clear my nether throat;

but had I come prepared, then had I delivered something worthy.
Bear with me, please your grace, till I can make amends.