Makarov established a 'swear jar'. Whenever someone swore, that's an automatic one hundred Jewels in the jar. This meant Natsu, Cana, Gray and Gajeel lost nearly all their money in the first week or so.
By the popular demand of the guild, Laxus went to talk to Makarov about it, and found him lying on the floor of his office, money half gone and with several bottles of booze around him.
"No one needs to know," Makarov winked then hiccuped. Laxus frowned. "But—"
"I'll buy you a new coat with this money."
"Deal."
Eventually the guild found out, and when they did, Makarov was forced to go without booze for a month. Laxus got out without punishment, and Natsu even complimented his now deluxe comfy coat the next day.