Good evening,
Waylay is an effect in the "Other" effect group as per page 98 of the ARB. Any effect can be used as a carrier attack at Plot's discretion (though ARC would advise that Plot carefully consider the ramifications of some effects before using them as carrier attacks). "Carrier" as a term is never defined very well in the rulebook, but at the end of the day it's simply a reference to using an effect with a weapon swing.
Note that while Slay, Eviscerate, Terminate, and Assassinate all have explicit exceptions allowing their combination with a normal weapon carrier (Normal, Silver, etc.) Waylay does not. When used with a weapon, it is the only carrier allowed to be called on the swing.
Thank you,
Bryan Gregory
ARC