gender-free, verbose, condescending explanation that was not asked for nor needed. Typically patronizing and incorrect.
Jeff: So I watered the lawn and plants last night and...
Chad: Did you remember to put in the electrolytes and do it from the top down? From the top down. Add those electrolytes. If you don't do it right the grass grows in sideways and won't seed properly. Not to mention they'll no longer use the sun for photosynthesis.
Jeff: Dude - Why did you assplain this to me?
Jon, commenting about a music video someone had posted under Meg's status update that her nephew had died without writing anything to acknowledge her loss, was really asshatian of you (...was really 3>ian of you).
The answer to a query that sounds plausible or as though the respondent is aware of factual data regarding the answer but is really just pulled out of the respondent's ass (see talking out of your ass)
"I asked him about the importance of religion in society and he gave me some assplanation about the subjugation of the masses."