Voiceless bilabially post-trilled dental stop

Trilled affricates, also known as post-trilled consonants, are consonants which begin as a stop and have a trill release. These consonants are reported to exist in some Northern Paman languages in Australia, as well as in some Chapacuran languages such Wari’ language and Austronesian languages such as Fijian and Malagasy.

In Fijian, trilling is rare in these sounds, and they are frequently distinguished by being postalveolar. In Malagasy, they may have a rhotic release, [ʈɽ̝̊ ɳʈɽ̝̊ ɖɽ̝ ɳɖɽ̝], be simple stops, [ʈ ɳʈ ɖ ɳɖ], or standard affricates, [ʈʂ ɳʈʂ ɖʐ ɳɖʐ].

Most post-trilled consonants are affricates: the stop and trill share the same place of articulation. However, there is a rare exception in a few neighboring Amazonian languages, where a voiceless bilabially post-trilled dental stop, [t̪͡ʙ̥] (occasionally written "tᵖ") is reported from Pirahã and from a few words in the Chapacuran languages Wari’ and Oro Win. This sound also appears as an allophone of the labialized voiceless alveolar stop /tʷ/ of Abkhaz and Ubykh, but in those languages it is more often realised by a doubly articulated stop [t͡p]. In the Chapacuran languages, [tʙ̥] is reported almost exclusively before rounded vowels such as [o] and [y].

...
Wikipedia