There's so few dragons compared to the other races on Azeroth...it stands to reason that a few of them would be pent up. >:P

Which other "dragons" are you refering to? I can only think of one (Neltharian/Deathwing), which certainly doesn't make the entire dragon race perverse.

Malygos: wanted to kill all non-dragon magic users.
Onyxia: general "I want to rule the world" plans; political machinations as well.
Nefarian/Sinestra: wanted to create new dragonflights for their general "I want to rule the world" plans.
Nozdormu (if he's going insane, current plot lines say he possibly is): wants to screw over Azeroth's time line.
Ysera (if she's going insane, I haven't heard of proof in either direction): she'd be more worried about destroying Azeroth through the Emerald Dream, not raping other dragons to further her own cause.

Maybe the sexual aggression has something to do with their reptilian aspects. Male iguanas can become extremely violent when they reach maturity, even attacking human females.

Neophobos, Maly kidnapped and corrupted Keristrasza, a female member of the red dragonflight, in an effort to have her replace his dead consort.