魔乳

魔 (ma, “witch; demon”) +‎ 乳 (nyū, “milk; breast”).

• On’yomi: Goon
• (Tokyo) まにゅう [mànyúú] (Heiban – [0])[1]
• IPA^(key): [ma̠ɲ̟ɯ̟ᵝː]

魔(ま)乳(にゅう) • (manyū) 

1. witch's milk
2. (slang, uncommon) large breasts
   • 2016, “Konnani atta! ‘Deka na oppai’ no samazama na yobikata 15-sen”, in Aol News‎:

     この業(ぎょう)界(かい)ではおっぱいを表(あら)わす単(たん)語(ご)としてどんな言(こと)葉(ば)が使(つか)われているのでしょうか。 […] 「魔(ま)乳(にゅう)」まがまがしいですね～。

     Kono gyōkai de wa oppai o arawasu tango to shite donna kotoba ga tsukawarete iru no deshō ka. […] “manyū” magamagashii desu ne~.

     In this world, what kind of words are used to stand for boobies? […] “Manyū (demon tits)”: Sinister, isn't it.

• (witch's milk): 鬼(き)乳(にゅう) (kinyū)
• (large breasts): 巨(きょ)乳(にゅう) (kyonyū), 爆(ばく)乳(にゅう) (bakunyū), 超(ちょう)乳(にゅう) (chōnyū)