Yay my second alien sex question, I hope I am not arrested.
Okay now to nitty gritty, So I got an intelligent species of Ostrich/flamingo looking creatures(this refers only to the shape, very few other aspects are like them)called the QiLokzmcs. And their method of reproduction involves a hybrid of the methods of the dart slug, bed bug, and the octopus. Basically what occurs is the males and females live in separate colonies and societies and for their mating rituals the males ambush a group of females and impregnate them with the hundreds of love darts around their neck that look like thick hairs. It doesn't matter where it hits them just as long as it does, just like bed bugs. these darts are more like tentacles as they are not hard and have little brains inside them which coordinate the darts on how to proceed.
What pressures and reasons would cause this reproductive method to develop in this species?