Cumthrax

That act of ejaculating into a postage envelope with malicious intent to the receiver.

“I will admit that on the seventh of May, 2009; I (name) send a letter containing Cumthrax to the owner of Monticello.”

Cumveloping

That act of ejaculating into a postage envelope out of spite for the sender or because it was there. This may be done with or without the intent of mailing it to the sender.

"My old church keeps sending envelopes to collect offerings from me, but they just become Cumvelopes."
Cumvelope Cumveloping