Penis. This is one of the few words in Russian slang which actually is of Tatar origin. Alternatives: елда, елдак, юлда, ялда.
Весь род Мудищевых был древний,
И предки нашего Луки
Имели вотчины, деревни
И пребольшие елдаки.
The entire Mudishchev family was ancient,
And the ancestors of our Luka
Had estates, villages
And enormous cocks.
(Лука Мудищев)