I think you need a reliable source of an upscale soft core content, just like celebsroulette. If you post clips less then 15 minutes and credit the source they will leave you alone ( no DMCA shit), I know I would. Anything else spells trouble.
If you flood it with the crap like Redtube at al, you are too late. Soft core niche works if it is done well.
Your 50 K + Alexa must drop to about 10 K then you will be rocking...