Reflexive for objects?

[circeus]

In a reflexive voice, one reduces valency by equating a subject and an object (less commonly a subject and an oblique or something that can be roughly construed as an oblique, such as a possessor: il se casse le bras "he breaks his own arm"). Is there a known instance of a voice that equates an object and an oblique? An "object reciprocal" voice, so to say: I rub/fold it against itself, I glue/sew/press it to itself etc.

[cedh]

I can't think of an example, but I believe many languages can do something like that. However, I think it usually wouldn't be used with sufficient frequency to get grammaticalized to the degree of a typical "voice". As in your English example, it would likely remain periphrastic. And even if it did grammaticalize into an affix, I suppose most linguists would treat it as a derivational operation rather than an inflection, considering that semantically it could be said to be a combination of two more typical valency-changing operations that are themselves often treated as at least semi-derivational, namely a causative of a reflexive. (Alternatively it might perhaps also be interpreted as a reflexive operator added to an applicative.) I would also guess that languages able to express such a category purely morphologically would be likely to do so with a combination of the two basic morphemes rather than having a separate unitary morpheme for "object reflexives".

[akam chinjir]

Causatives of reflexives are definitely attested. Checking some likely places, I found Bantu, Quechua, and Turkish examples. Baker, The Mirror Principle and Morphosyntactic Explanation has some examples in section 4.1 (starting p.391).

[Curlyjimsam]

It would be interesting to see this sort of reflexive marked on the preposition:

I folded it against-REFL (it) = "I folded it against itself"

[Xwtek]

It would be interesting to see this sort of reflexive marked on the preposition:

I folded it against-REFL (it) = "I folded it against itself"

Like in Takelma language?

[Ryan of Tinellb]

I thought High Lulani might have something like this, so I searched my dictionary for self or reflexive. Turns out I did originally, but I repurposed that word to be "third person topic pronoun" long ago without actually updating the dictionary. Oops.