Here's the info on anal sex in Singapore - it's alright between
man and woman but not between two men.
http://eresources.nlb.gov.sg/infopedia/articles/SIP_1639_2010-01-31.html
One of the changes was to decriminalize oral and anal sex between a
male and a female (section 377). However, section 377A which
prohibited oral and anal sex between two males was
retained.