1 You flirt a lotBe conscious of the sexual energy you radiate. Excessive sexual familiarity is a dangerous thing. It inadvertently leads to relinquishing sexual boundaries. Be mindful of intimate remarks and gestures, lest it gets misconstrued.
2 Your want too much of her/his timeThis seems to be a natural fallout of a close platonic relationship. Wanting too much of your friend's time, spending too much time in that person's company, calling too often are all danger signs that can spiral out of control. Stop short of too much neediness.
3 You fantasize about sexThe essence of a platonic relationship is its non sexual character. Compromise that and you land in trouble. Be watchful of your flights of fantasy with your platonic friend. This has the potential to be gets habitual and create unwarranted attachment. Check it.
4 Don't talk sex with each otherThis is far more dangerous than daydreaming actually. You could lead the person on. Yes, your friend is somebody you could talk to about anything in the world, family issues, work, politics, relationships etc. Truth is anything but too intimate stuff. Be mindful of what you say. Filter your thoughts. Too graphic sexual details can be damaging to a platonic friendship. Never discuss your sexual intimacy with another person.
5 Stop short of discussing your 'best buddy' with the worldThis is a slippery terrain. You know that person's your best buddy. But the world has different bars for judging what this 'best buddy' tag implies as perceptions wary. Worse, if you happen to have common friends. Your friendship is a personal matter. Leave it that way.
6 Platonic friendship vs romantic friendRemember, passionate love has no place there. Your love may be chaste - pure love and unconditional support. It takes very little time for this get out of hand. Romantic love could also be pure and full of support. The essence of success in platonic relationships is to know where to draw the lines.