You have to understand that when someone has sex with someone of the opposite sex, that does not mean that he or she cannot have sex that is just as good with someone of the same sex, and vice versa.
You never know what another person’s sexual template is and at the same time you cannot look at someone and determine whether or not he or she is attracted to men and women, only women, or only men. Since you can never judge a book by its cover. Never assume anything!
When in doubt, look him/her in the eyes and ask, “Are you attracted to both men and women?” “Have you ever had sex with another man/woman?” Be direct and be serious! Take safer sex precautions with everyone, and NEVER assume that he or she is either too feminine or too masculine to “get down” with members of the same or of the opposite sex.