Bringing unnecessary attention to the situation. Pointing it out to your buddies and purposely harassing the couple with gazes and leers. Walking over to the couple and getting into their personal space and purposely invading their privacy.
"Oh yeah! that's so hot!" "That's what I like to see!" "Keep doing it girls!"
Man's Reaction Explained
This is the typical male response when girls make out. Regardless if they are straight or not. I think it is because men already find women to be attractive in the first place, so the action of two women kissing; will naturally double the amount of sexual bliss that men will receive. However the issue arises when men become total creeps and deliberately gawk at the couple trying to enjoy themselves. Keep your comments to yourself and give the couple the same privacy they would give you and your girlfriend.
Oh, you find me kissing another girl attractive? I never knew that. I never knew that two girls kissing turned men on. It's not like pop culture constantly objectifies and exploits female homosexuality for the male gaze while acting horrified by two men kissing. How nice of you to interrupt my wonderful, romantic, personal moment with your revolting sexuality. If I was interested in you I would be kissing you. If I was interested in men I would kiss men. I'm not, I'm kissing a girl because the idea of touching you is about as appealing to me as the idea of banging dudes is to straight guys. When you take my moment and make it about you, it's not ok. It's unbelievably self absorbed and inconsiderate for you to bother two people- because women are people- and make their sexuality about you with their consent. It's not flattery, it's harassment and it's pathetic.
Lesbian Reaction Explained
Guys, imagine this scenario- you're walking down the street with a beautiful girl and not only does she like you, but she likes you so much she wants to kiss you. Isn't that an awesome feeling? Doesn't it make you really happy when a girl likes you so much she not only wants to touch in private, but she wants to touch and kiss you in public for all the world to see. Doesn't that make you happy? Now what if that moment was interrupted by a group of large, leering gay men who look at you're all buttered up and ready for boy's night. But they're just not looking- they're commenting. "Yeah, yeah keep doing that. That's what I like to see. Kiss her again! More tongue."
Would that not be a massive WTF MAN moment? You're minding your own business, walking down the street in America (Land of the free!) and these clowns you have no interest in are ruining a perfectly good kiss while making you and your partner incredibly uncomfortable. That's not cool, and this sort of behavior isn't the exception- it's the norm. Go on guys, ask a girl how they feel when a guy harasses them in public. Now ask a lesbian how guys act when they kiss a girl in public. You're so blinded by the "Girls Gone Wild XXX" fantasy that you actually think women kiss women just for your pleasure. I get harassed more than half the time I kiss a girl or hold a girl's hand in public, and I live in the very liberal and jaded city of Los Angeles. It's not because I am (or think I am) hot shit- it's because I'm a girl, and this is the way girls are treated.
I get that sometimes guys can't help getting turned on by two girls kissing, but guys can easily stop staring, yelling, and insulting women. It's terribly uncool and all girls around you who aren't gay are now thinking what a loser you must be. Go home, take a bathroom break, and quit ruining my dates.