So I really want a Plusle so I looked up how to breed a Plusle and apperently it can be done by breeding a Jigglypuff and a Clefairy. I have a Level 57 Jigglypuff (male) and a level 50 Clefairy. Will it work? If not, fo you know any pomemon that can be bred to get a Plusle (black 2 only please)? Thank you!
You are mistaken. Plusle is in the same egg group as the two in question. Because they are both in the Fairy egg group it is possible to breed a female Plusle with a male Pokemon from the Fairy egg group. Which means to breed a Plusle you would first need a female Plusle.
See here for more information.
Your not out of luck though. In Black 1 and 2 after game completion you can come across swarms of certain Pokemon that are not native to the region. Plusle can be found on route 6 in swarms once every so often.