And to specifically answer your question, you can post songs in the 12" Reviews forum (see here) as long as you ask for feedback. We're not a community where you can upload a million songs in five minutes and not expect leechers to steal the link until it expires and then you have been unsuccessful by not allowing the real DJs and music lovers to get a taste of it.
Phew, that was a mouthful. Basically, just stick around and get to know the community. It is all right to share music and receive feedback in the forum listed above, just don't request music. Okay? I hope this helped.