If we assume spin as in spinning around its own axis, and there’s a breeze, we can calculate lift like we would for a Flettner Rotor.
Assumptions:
- your dick is a perfect cylinder
- no slip condition regardless of speed
- wind is constant at 5m/s
- Air density is assumed to be 1.2kg/m3
- you can somehow keep your dick perpendicular to the flow and ignore the moment that would be caused by all your weight on one side (perhaps you have a perfectly identical twin and you are strapped back to back doing the exact same thing)
Equations:
$L’ = (1.2)(5)(2\pi)(\omega)r^2$
$F = L’ l$
$F > W = mg$
Giving us a solution of $\omega > mg/(12 \pi r^2 l)$, where omega is the rotational speed (rad/s), m is your total mass (kg), g is the gravitational constant (m/s^2), r is the radius of your dick (meters), and l is the length of your dick (also meters).
Results:
Given my own measurements the angular velocity required would be a little under 40,000rad/s or around 750,000rpm (assuming my math is right). For reference that’s about 250x faster than a jet engine fan.
Discussion:
Most likely your dick would be ripped apart by centrifugal force (yes I’m aware that’s not a “real” force unless you choose the rotating reference frame but we should choose the reference frame of the dick anyway so it’s fine) before you got off the ground because that is the minimum speed to generate enough lift to barely cancel gravity.
Further Work:
Clearly the logical next step is to build a strong but light shell around the dick to prevent explosion. Other ways to mitigate angular momentum problems would be to replace the subjects blood with a less dense fluid to reduce the mass and, as a consequence, the moment of inertia of the dick.