A straight man is one who is heterosexual.
A straight man is heterosexual, meaning his romantic and sexual attraction is exclusively to females. Straight men are also considered sex objects by some gay men, who enjoy the challenge of attempting to convince straight men to have sex with them or find it erotic watching straight guys masturbate.
The word "straight" was first used by author GW Henry in 1941. He said that "to go straight is to cease homosexual practices and to indulge - usually to re-indulge - in heterosexuality". Although the word was not originally used to refer to heterosexual men, over time it began to be used this way and that practice has continued in both straight and gay communities.
Straight men are often showed in certain kinds of porn as being tricked into gay sex. The straight man in question may be drunk, asleep or may be fooled into thinking a woman is stroking or sucking his cock when in reality a man is. In porn, there is a category nicknamed "gay for pay". In gay for pay, straight men in need of money are convinced to have some kind of sex with another man on camera for payment. Sometimes the men shown in these sites are actually gay porn actors, but some sites run ads for straight men who are interested in being in an adult video. A straight man is often perceived by certain gay men as the same kind of sexual target that a lot of straight men see woman as.
The term straight is sometimes used by drug addicts to describe living a drug free live.