Unnatural SEX.
under section 377. Whoever voluntarily has carnal intercourse against the order of nature with any man, woman or animals, shall be punished with imprisonment for life, or with imprisonment for a term which may extend to 10 years, and shall also be liable to fine.
Explanation.
Penetration is sufficient to constitute the carnal intercourse necessary to the offence described in this section.
The prosecution must prove:
(i) that the accused had carnal intercourse with a man, woman, or animal;
(ii) that such intercourse was against the order of nature;
(iii) that the accused did the act voluntarily; and
(iv) that there was penetration.19
**So far, Singapore courts have accepted anal intercourse and bestiality as ‘carnal intercourse against the order of nature’,
As for Fellatio/oral sex There appears to be a linguistic struggle to include fellatio within the scope of 377
for more information on section 377. read here
http://www.lawgazette.com.sg/2004-9/Sep04-feature2.htm