Chinese.
Dì di / xiăo dì di (弟弟/小弟弟

- literally 'little brother'; slang for penis.
Jī bā / Xiăo jī jī (鸡巴/小鸡鸡

- slang for penis; used by northern and mainland Chinese; not commonly used by Singaporean Chinese. Usually abbreviated to "JJ", especially on gay Chinese websites.
Yīn jīng (阴茎

- scientific word for penis.
Bī (屄

- classical Chinese word for vagina; not used by Singaporean Chinese.
Yīn dà o (阴道

- scientific word for vagina.
Dă shǒu qiāng (打手枪

- Mandarin translation of Hokkien slang meaning male masturbation. (lit: firing a handgun)
Dǎ fēi jī (打飞机

- slang for male masturbation, the imagery being anti-aircraft fire or spunk flying out like an airplane.
Shǒu yÃn (手淫

- scientific word for masturbation.
Pì gǔ (屁股

- buttocks or anus.
Gāng mén (肛门

- scientific word for anus.
Gāng jiāo (肛交

- scientific word for anal intercourse.
Luà n jiāo (乱交

- scientific word for promiscuous sex.
Kǒu jiāo (口交

- scientific word for oral sex.
Piáo (嫖

- to go whoring.
Diǎo (a "门" with a "小" inside it; or 屌

- Mandarin translation of Cantonese slang meaning "to fuck".
Gǔn dà n (滚蛋

- fuck off!
Cāo (肏; sometimes wrongly written as 操

- northern Chinese slang for fuck, not used by Singaporean Chinese.
GÃ n (干

- milder northern Chinese slang for fuck, not used by Singaporean Chinese.
GÃ n cao (干操

- northern Chinese slang meaning to fuck, not used by Singaporean Chinese.
Liao - to rim (eg. an anus with the tip of the tongue).
Xī (吸

- to suck.
Rǔ fáng (乳房

- scientific word for breast.
Rǔ tóu (乳头

- scientific word for nipple.
Jī (鸡

- literally meaning "chicken", slang for "female prostitute".
Yā (鸭

- literally meaning "duck", slang for masculine "male prostitute" or "gigolo".
Jì nǚ (妓女

- proper word for "female prostitute".
Tā mā de jī dà n (他妈的鸡蛋

- literally 'his mother's eggs'; 鸡 (jī

is an oblique reference to the Hokkien 'chi-bai' meaning 'cunt' (see below). Thus, the expression is akin to the English use of 'shoot' as a milder substitute for 'shit'.
Jī dà n gāo (鸡蛋糕

- literally 'cake made with eggs'. Also an allusion to the Hokkien 'chi-bai', used in a similar way as the previous expression.
Bā pó (八婆

- Mandarin translation of Cantonese slang for bitch.
Sǐ sān bā/Chòu sān bā (死三八/臭三八

- bitch.
Huaì dà n (壞蛋

- literally 'bad or ruined egg.' "bastard"
Wáng bā dà n (王八蛋

- son-of-a-bitch; bastard.
Biǎo zi (婊子

- Northern Chinese slang for bitch, not used by Singaporean Chinese.
Some slang words have no direct Chinese characters to represent them.