Pity the Love Fool in the locations specified below.
This is one of the achievements needed for the Love is in the Air holiday meta achievement Fool For Love.
To complete the achievement, you will need one Love Fool for each of the required locations (five total). These can be purchased for ten Love Tokens each from vendors during the holiday. Travel to the location, drop one on the ground, target it and type /pityfor credit.
As a tip, it does not need to be your own Love Fool to receive credit, so you can save on the Love Tokens cost by grouping with friends or hoping you get lucky by encountering another player in your random dungeon or battleground completing the achievement.
Note: Characters must be at least level 80 in order for them to earn this achievement because Naxxramas is a Wrath of the Lich King raid instance.