moe buta 萌え豚

In Japanese, moe buta 萌え豚, "moe pig," is a derogatory and often self-depreciating slang referring to a type of otaku that likes manga and anime focused on moe 萌え.

In other words, it refers to anime fans that like anime with lots of cute girls and bishoujo 美少女 characters. It's derogatorily because they're admitting they'll watch anything if the author puts a cute girl in it. They're easily bought with cuteness.

If you give them moe, they'll flock to you like pigs.

Manga: Blend S, ブレンド・S (Volume 3, Page 16)

ブヒる

Since moe pigs are pigs, they make the sound a pig makes: "oink," buhi ブヒ. As a verb, it becomes buhiru ブヒる, "to squeal." This verb would have the same meaning as moeru 萌える, "to feel moe," when in the context of moe buta.

Manga: Danna ga Nani wo Itteiru ka Wakaranai Ken 旦那が何を言っているかわからない件 (Chapter 1, 合わない趣味とハマったソリ)

Context: a wife watches her husband watch Lucky Star.
uhaa~~ moe~~
ウハ～～萌え～～
Woohah~~ moe~~
buhii~~
ブヒィ～～
*oink*
suki danaa...
好きだなぁ･･･
[You] like [it], [don't you]...?

Usage

For reference, an example of the term moe buta being used:

Manga: Blend S, ブレンド・S (Volume 3, Page 16)

Context: Kanzaki Hideri 神崎ひでり wants to be a moe idol instead of working in a farm.
mushi ni kakomareru no wa iya daa!
buta ga... 'moe buta ga ii--------!!
虫に囲まれるのは嫌だぁ！
豚が･･･っ萌え豚がいいーーーー！！
[I] don't want to be surrounded by bugs!
Pigs... moe pigs are [better]!