I tried to use dForce but it doesn't work this way. I'm so noob for Daz Studio... please help me out
Depends on if you wanted to show the bulge of the penis in the skirt or not...
If not - then just hide the penis.
If you did want the bulge, then what
Nicke said above applies. You need to start with the skirt draped out so it's above the penis and doesn't clip through, otherwise the Dforce simulation won't work normally. Also, I'm pretty sure most Dforce assets don't play well with Dicktator morphs. They tend to ignore the geometry of the penis.
A work around I have used for this is to make a primitive cylinder, roughly the same size as the penis. Then, using your timeline, place the cylinder in a down pose and rotate it up to the final pose in about 15 frames or so. Hide the actual penis while you do this. And make sure to start the simulation with the skirt well out from the cylinder.
If it works properly, the skirt will initially drape down and then the cylinder rotating from "nose down" to "nose up" will push the skirt out to roughly where you want it. Do final tweaks with Meshgrabber.