吮

to suck

吮 character breakdown

吮
- 允
  - 儿
    - 丿
    - 乚
  - 厶
- 口

just / fair / to permit / to allow

允 = 儿 + 厶 : Sun Wukong (儿) has a runny nose (mnemonic symbol for 允) and is constantly blowing his nose in the encampment ((e)n3). Yu the Great (yu) is very annoyed and tells him that it is not allowed (允) to blow one's nose in the encampment. Instead she hands him a fake nose (厶) with which he is to hide his real nose.

口

kǒu = k + ou3

mouth / classifier for things with mouths (people, domestic animals, cannons, wells etc) / classifier for bites or mouthfuls

Mnemonic symbol: 口 shall be represented by a mandarin. Karl Marx (k-) is enjoying a mandarin in the outhouse's living room (ou3).