comment stolen from Wowhead "Found at 64.4, 65.9 in Frostfire Ridge, ABOVE the Thunderlord Clan base (the Huge dead Grom) and in the nest you will find the Mysterious Egg that gives you this item (after 3 days)."
hope it helps
edit: I see someone posted the coords below....I can't figure out how to delete my comment...so downvote it to oblivion
comment stolen from Wowhead "Found at 64.4, 65.9 in Frostfire Ridge, ABOVE the Thunderlord Clan base (the Huge dead Grom) and in the nest you will find the Mysterious Egg that gives you this item (after 3 days)."
hope it helps
edit: I see someone posted the coords below....I can't figure out how to delete my comment...so downvote it to oblivion