My favorite Cosmo tips:
1) "Suck on a cough drop and go down on him. The cool minty feeling will drive him nuts!" The one thing I actually did try when I was young and completely inexperienced. My then-fiance ended up with a mild chemical burn on his penis.
2) "When going down on him, sneak a finger or two into his butt! He'll hit the roof!" Well, they certainly told the truth on that one. The problem is the word "sneak", which suggests that you didn't ask first, and the "or two", which if you didn't ask, and are sneaking around and not using lube, I think any guy would freak to have two fingers suddenly in his butt. The roof he's likely to hit is the roof of your mouth, which would likely cause you to bite down. Either way, that'll land you in the ER quicker than the cough drops.
3) "After sex, grab your used panties from the floor and use them to tie your hair back! Not only will this show him that you're fun and casual, the intoxicating smell of your womanhood will get him turned on again!" Because every man goes crazy for a woman with underpants on her head! Especially dirty underpants! I don't think that will show you off as "fun and casual" so much as "making the man in question worry if he's going to be facing criminal charges for having sex with a woman obviously not in her right mind".