go to shadowmoon valley and find the place full of neutral felboars (which you must protect from flayers)
Domesticated Felboar - NPCs - World of Warcraft
there, go close the NPC quest-giver (its a vendor too) and kill the felboars, the spawning time is about 1-2 minutes, you can tape them and let a 70 do the dirty job...
40k exp non rested in 14 minutes, not bad at all.