Hello and welcome !

Your post reminds me of a picture of John Lennon holding his guitar upside down trying to get his pick out. If it can happen to him, it can happen to any of us!

A few tips that you may find helpful:

1) Try different types of picks, Some have nice grips that prevent slipping. They also come in different levels of flexibility. A more flexible pick may help. It helped me.

2) Try holding the guitar so that the strings are perpendicular to the floor. That way, if you lose your grip, it will usually will fall on the floor instead of in the sound hole.

3) When strumming, try to lead a bit with your hand so the pick strikes the strings at such an angle so that it glances off the strings rather than slamming into them. It takes a bit of practice but before long you`ll get the feel of it.

I`m sure more experienced players can offer more insight. Hopefully this helps.

Jeff