http://revach.net/article.php?id=4913

Section: Shabbos   Category: Minhagim
A Hot Drink On Motza'ei Shabbos To Take Away The Blues

The Gemara (Shabbos 119b) says that hot water and hot bread on Motza'ei Shabbos can heal you. Rashis says hot water means to drink and wash yourself. From these three things, writes the Minhag B'Yisroel Torah (OC 300:2), only drinking hot water is a minhag that has been widely accepted. While he says that a few Yechidim including the Maharam Ash were noheg to eat hot bread, no on is noheg to be makpid to wash in hot water.

There are a number of reasons given for drinking hot water on Motza'ei Shabbos. One of them comes from the Rebbe Reb Zyshe, who said that hot drinks are a cure for sadness. He brings a remez for this from the words in the pasuk HaRofei Lishvurei Lev U'Michabesh L'Atzvosam, He cures the broken hearted and cures their sadness (Tehilim 147:3). Michabesh he says is the Roshei Teivos for Ches - Chamin, Bais - B'Motza'ei, Shin - Shabbos, Mem - Milugma. The hot watrer of Motza'ei Shabbos is a balm for sadness.

The Orchos Chaim says that when you do drink your hot drink on Motza'ei Shabbos you should says "Chamin B'Motza'ei Shabbos Milugma".