I presume that you're concerned about "rocking" the lens when cleaning the glass? If so, then I share your concerns. The extended lens (as with any camera with a retractable lens) is a rather delicate arrangement.
I've taken to cleaning the lens by laying the RX100 on its back - with lens extended - and gently holding the outermost section of the lens between forefinger and thumb, to constrain sideways movement. Then I gently clean with a lens cloth as per the comment by bartjeej... with considerable emphasis on the word "gently"...
I don't know if this method is recommended by Sony, but it makes sense to me. It's not my recommendation - only a description of my way of doing it. Therefore, caveat: use only at your own risk!
I used a sensor swab and cleaning fluid on one of my rain marked lenses. It worked a treat. I thought if its gentle enough for a sensor it would be ok on a lens. And no force required. Bit of an expensive way of doing it though