I claim the ornamental design for a vaginal steamer, as shown and described.
FIG. 1 is a front view of a vaginal steamer;
FIG. 2 is a rear view thereof;
FIG. 3 is a right side view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a top view thereof;
FIG. 6 is a bottom view thereof; and,
FIG. 7 is a rear view thereof in a condition of use with a toilet seat.
The broken lines in FIG. 1 depict a portion of the vaginal steamer that forms no part of the claimed design, and the broken lines in FIG. 7 represent an environment and are for illustrative purposes only; the broken lines form no part of the claimed design.