so that's the problem it turns out need a bigger dickThe thrusting is always smooth, no matter the settings.
Twitching is caused by the male almost poping out. In this case the direction is reversed instantly to avoid that. Use a larger dick or put it further in.
Alternatively, uncheck "Prevent PopOut". But do this on your own risk.
but it doesn’t look aesthetically pleasing, not everyone has a half-meter penis