Subsequent flight reviews may be done in any aircraft that you are
qualified for, however the practical requirements are different. For a
glider you may substitute three flights in lieu of the one hour
requirement. There is also a requirement for one hour of ground
instruction. The review must be given by a CFI, DPE, or FAA inspector.
Here's a short blurb that describes the requirements:

Requirements Of FAR §61.56

FAR §61.56(a) states that a flight review consists of a minimum of one
hour of flight training and one hour of ground training. However,
glider pilots may substitute a minimum of three instructional flights
in a glider, each of which includes a flight to traffic pattern
altitude, in lieu of the one hour of flight training.

The training must include a review of the current general operating
and flight rules of FAR Part 91 and a review of those maneuvers and
procedures that are necessary for the pilot to demonstrate the safe
exercise of the privileges of the pilot certificate. The authorized
instructor giving the flight review has the discretion to determine
exactly what maneuvers and procedures are included in the flight
review.

FAR §61.56(c) goes on to say that the flight review must have been
accomplished within the twenty-four calendar months preceding the
month in which a pilot acts as pilot in command in an aircraft for
which that pilot is rated. The authorized instructor must also endorse
the pilot's logbook certifying that the pilot has satisfactorily
completed the flight review. A pilot's demonstration of competency in
any aircraft satisfies the requirements for all other categories or
classes of aircraft for which the pilot is rated.

If a pilot performing a flight review with an authorized instructor is
denied a satisfactory endorsement for flight review, the pilot may
continue to exercise certificate privileges provided the twenty-four
month period has not elapsed since the last flight review. However, if
a pilot performs a flight review with an FAA inspector and does not
receive a satisfactory endorsement, the pilot would not be able to
exercise the certificate privileges until successfully completing a re-
examination practical test under 49 USC 44709 (the "709 re-
examination" formerly called the "609 re-examination").