When it comes to sex, female fish lay eggs and then the male does the Dew atop of them, so if that is in Spongebob, that means the female with basically give birth to egg(s) and then the male [yanks the stick] atop of it and there you go. So, it would depend on the species: Like for example, if it were to be a male crab and a female fish, they would actually have to do the Dew as well as the female then having to actually give birth for real. Now, what if it were the opposite? Well, that would mean it would end up being that they would have to do the Dew in the missionary position as most crabs do it (yes, I actually fucking did the research). Now, what about say, a sponge and a starfish? Well, if it is two starfish, the male sends the semen into the water as the female does the same with the egg. With sponges, they can do it asexually, but I will focus on the sexual way. The male sponge does the same as the male starfish and sends it into the water. However, it has to do it into the water column. So if it were to be a male starfish and a female sponge, the starfish would simply have to do the same as the male sponge does. If it were to be the other way, the sponge has to simply do the same as the starfish and it is as easy as that. Now, what if it were to be a whale and a squid, it would require some different methods. A female whale actually has to give birth as a female squid lays eggs like a fish. So if it were to be a female whale and a male squid, the squid would have to find a way to get the sperm into the whale. If it is the opposite, it is as simple as the fish, but there will be a overflow of [sticky white stuff]. That is all for now. Oh, and for the porn part, all they do is get a third character with a camera and done.