arctic_sg SG Of the three you listed, so long as you don't cause any harm and restrict to on butt and not IN butt, you are on the safe side of the law.
asparagus SG the position of the comon law wrt oral sex isnt so strict now. just last yr justice yong ph said that oral sex is okay if done between a consenting heterosexual couple of legal age, provided that they have normal, vaginal sex after or before that.