When my wife has wine after dinner, she sleeps very soundly. One night when I finally got to bed (about an hour after she did), I was feeling sort of randy, and slid my hand over until it reached her leg. I noted that she was wearing a negligee, and with very little effort (lifting the negligee), I confirmed that she was not wearing panties.
I moved my hand so as to lift the covers, and hover above her pubis, then slowly allowed the covers to sink back down along with my hand, which was now over her pubis but with the negligee in the way. I tried to keep from pressing harder than the covers, but eventually pushed one finger down between her labia, watching to see if she wakened. My goal was to wait until she was dreaming, but there was not enough light to look for the "rapid eye movement" that is supposed to accompany dreaming.
Slowly and gently I pushed her labia from side to side, moving her clitoris beneath her labia, but not touching it.
She did not move nor make any noise; I considered that maybe she was awake and just enjoying the more leisurely stimulation she was getting (compared to my usual kiss and fuck routine). Suddenly she made a vague noise and turned away from me to sleep on her side, but she said nothing and her breathing was regular. I waited a minute or so, and used her upper leg to move her back flat on her back, while also moving her leg apart a little, and moving the negligee up out of the way. My one finger could now burrow down between her labia, over the hood of her clitoris, nowhere near the more sensitive area that is identical to the most sensitive area of the penis (the frenulum, just below the glans).
My finger slowly gently flipped her clit from side to side as my finger pushed against the hood and shen slid over it when the pressure was great enough.