The main occupation of the Karakullukçu was to serve the Karakol stations.
The initiation of a novice to be a Karakullukçu:

And after a comrade (Yoldaş) in accordance with the Law, performs these services (of Karakullukçu), the Law (is that) he brings a sheep for the feast of the comrades, they hang it to the hook (for hanging meat) in the sofa of the Orta. That night, they cook the sheep and eat it. Then with prayers and praises (to God) they permit the comrade to wrap a dülbend²⁴² around his plain arakiyye²⁴³. <sup>244

242</sup> Dülbend: A thin piece of cloth made of cotton with colorful patterns.
²⁴³ Arakıyye: A hat made of wool. Mostly worn by dervishes.
²⁴⁴ Kavanin-i Yeniçeriyan, p.175

“Baklava Alayı” (Procession for Baklava dessert):

On the fifteenth day of Ramadan, following the Sultan’s visit to the chamber of Holy Relics, a special dessert prepared in the imperial kitchen was given to the janissaries for celebration. The dessert was served on large trays and accompanied by their Master Cooks, they were taken by a team of Karakullukçu from each Orta.
The trays were placed on colorful sticks and each were carried to the barracks by two Karakullukçu. <sup>354

354</sup> Kapıkulu Ocakları, v.1, pp.257, 421.

Source: Janissary and Samurai: Early Modern Warrior Classes and Religion by E Küçükyalçin 2007