Dreaming about public indecency

Background: I'm a 25 year old gay male with a pleasantly active sex life. Recently, within the past six months or so I would say, I've suddenly started to dream about masturbating in public.

I have one of these dreams usually every other night, although sometimes several nights in a row. Nothing in particular seems to trigger them and I'm not aware of anything that might have started it six months ago.

The dreams all follow a standard formula: I'm hanging out in a public venue -- sometimes a parking lot, somtimes a neighbor's front lawn -- church, work, the grocery store, the side of the freeway during rush hour, in my car during rush hour, on the set of a TV show, etc. when suddenly I dream that I have the irresistible and overpowering urge to masturbate.

I start doing the deed and usually end up getting arrested or otherwise "exposed" by family or friends (who are usually laughing at me). I'm not sure if it makes any more sense, but these dreams are usually immediately followed by dreams of catastrophic disasters (tornadoes, hurricanes, volcanoes, etc.). They so often follow each other, actually, that sometimes I wonder if they are just two parts of the same dream.

Normally I'm pretty relaxed when it comes to stuff like this but the frequency and vividness of the dreams is starting to disturb me. I'm not used to having ANY vivid dreams every night or every other night, let alone weird/nightmarish sexual dreams.

So, is this normal?

If not, is there anything I can do about it?