"Girls they want to have fun" by Brillant Software (more from this author)
This one's an evergreen for me! Controls are a bit strange
at the beginning. Twist and twirl your stick to move her hand.
Here are scans of the German instruction manual: [1] [2]
Can you beat Telespielator's score of 3271 points?

"Girls They Want To Have Fun II" by Uncle Ben's Soft (more from this author)
I'll quote Uncle Ben: "This can just be considered a demo and not a
game since you can't gain any virtual points. The pictures were taken
from other Demos/Diashows and improved a little bit plus I added the
vibrator-function which simply consists of two picture setups.."