I don't find them particularly attractive. There was a time about 20 years ago when they were new and novel and had some attraction for that reason, but there's nothing new in the piercing world anymore, and it's not an especially attractive piercing.
Plus, a lot of people will assume, for right or wrong, that you suck a lot of d!ck if you have a tongue piercing. That's not necessarily true, but that doesn't change how people will think.
The bottom line is that you don't have to poke holes in your body to be unique or attractive. And your personality will get you much farther than any piercing, or anything else about your looks, ever will.
Why I don't like them? Because it's a nail and a piece of metal you've buried in your skin (or tongue) and it just seems gross.. they're uncomfortable, prone to hitch to something and they don't really look that attractive.
I think they're kinda cool but I personally wouldn't get one because of the negative sexual connotation. Whether or not you just want it because of the style, it will affect the way people see and treat you. You will get attention from the wrong type of men. However, they're relatively easy to hide and you can get flesh colored rings if you want it to be even less visible.
You can always get your belly button pierced, most guys seem to find that cute and/or sexy.