The Edgeplay reference article from the English Wikipedia on 24-Jul-2004
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Edgeplay

Helping orphans the way you would do it
In BDSM, edgeplay is a subjective term for types of sexual play that are "on the edge" of the traditional safe, sane and consensual creed. These forms of BDSM activity are regarded by many as inadvisable and dangerous, and it is nearly universally held that they should not be attempted without proper training, supervision, safety precautions, etc. as appropriate.

Edgeplay may involve:

What constitutes edgeplay varies with the persons involved, and also over time. In the mid-nineties, the Living in Leather convention did not have panels on ageplay or scat because they were considered too edgy. By 2000 they were part of the regular list programming.