Would pointing several domain to a same site hurt SERP?

Hi guys, realizing that some of my domains which are currently parked do received some traffic here and there occasionally, but there seldom incurred any clicks in them and didn't earn me a good income, in fact they were almost zero.

So I am thinking, instead of wasting the potential trafic for these domains, wouldn't it be better if I were to point them to my main site which is developed and ready to received more traffic!

However, I am quite concern as to would doing this could potentially hurt my SERP or not? I have this concern due to such practise might be viewed as "bumping" or "blackhat" trick to the eye of major SE. I have no worries if I only point 2 or 3 domains, but I plan to build up a little bit of my domain portfolio and point them (about 20domains) to the main site, that's why I am little bit concern about this.

Or did I "over" anxious?

Should not hurt your serp at all. As long as you do a permanent re-direct the all the pr of those other domains will pass to the domain you are linking to, theortetically.