  We consider the motion of charged and spinning bodies on the symmetry axis of
a non-extremal Kerr-Newman black hole. If one treats the body as a test point
particle of mass, $m$, charge $q$, and spin $S$, then by dropping the body into
the black hole from sufficiently near the horizon, the first order area
increase, $\delta A$, of the black hole can be made arbitrarily small, i.e.,
the process can be done in a ``reversible'' manner. At second order, there may
be effects on the energy delivered to the black hole---quadratic in $q$ and
$S$---resulting from (i) the finite size of the body and (ii) self-force
corrections to the energy. Sorce and Wald have calculated these effects for a
charged, non-spinning body on the symmetry axis of an uncharged Kerr black
hole. We consider the generalization of this process for a charged and spinning
body on the symmetry axis of a Kerr-Newman black hole, where the self-force
effects have not been calculated. A spinning body (with negligible extent along
the spin axis) must have a mass quadrupole moment $\gtrsim S^2/m$, so at
quadratic order in the spin, we must take into account quadrupole effects on
the motion. After taking into account all such finite size effects, we find
that the condition $\delta^2 A \geq 0$ yields a nontrivial lower bound on the
self-force energy, $E_{SF}$, at the horizon. In particular, for an uncharged,
spinning body on the axis of a Kerr black hole of mass $M$, the net
contribution of spin self-force to the energy of the body at the horizon is
$E_{SF} \geq S^2/8M^3$, corresponding to an overall repulsive spin self-force.
A lower bound for the self-force energy, $E_{SF}$, for a body with both charge
and spin at the horizon of a Kerr-Newman black hole is given. This lower bound
will be the correct formula for $E_{SF}$ if the dropping process can be done
reversibly to second order.
