(No one has gotten this right yet!) An official "cleaveland steamer" is shitting on a girl's chest while receiving head, plain and simple. Now, there are certain ways to tweak the technique if you will. For instance, you can be having sex, and right before you're about to cum you pull out to put it in the girl's mouth, and then as you're cumming take a shit on her chest (bonus points!). It all depends on how creative you wanna get.
felacio + defecation on chest = cleaveland steamer