I claim the ornamental design for an attachment for an apparatus for simulating a sexual motion, as shown and described.
FIG. 1 is a top perspective view of the attachment for an apparatus for simulating sexual motion, showing new design.
FIG. 2 is a right side view thereof.
FIG. 3 is a left side view thereof.
FIG. 4 is a front view thereof.
FIG. 5 is a rear view thereof.
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The broken lines showing of Attachment is for the purpose of illustrating portions of the Attachment for an apparatus for simualting sexual motion, and form no part of the claimed design.