More on Tu:
1. Tu is very commonly used to address God (Allah, Khuda, Bhagawaan, Eeshwar, etc.), while Tum is slightly less common and Aap is extremely rare, except, for example, in Bhagawaan-jee and occasionally in Allah Mian.
2. Tu is almost never used with ceremonial/extremely formal verbs, e.g. Padhaarna (to come, arrive or enter) as in Aap padhariye (Hindi) or Tashreef laana (to come, arrive, enter or "bring one's presence") as in Aap tashreef laaiye (Urdu).
3. "Tu-Tadaak" (noun, usually feminine) is a somewhat derogatory term for a rude (often petty) argument, general rudeness/vulgarity in speech, or simply the use of the "vulgar" Tu and related terms (Tujhey, Tera, etc.). "Tu-Tu-MaiN-MaiN" (feminine noun, literally "You-You-I-I", a slightly stronger version of "Nok-JhoNk") is another common term for a heated or rude (often petty) argument/quarrel.
Woh (that) / ladkaa (boy)/ toh (exclamatory word)/ tu-tadaak (vulgarity/rudeness in speech)/ par utar aayaa (descended to).
Saas (mother-in-law) / aur (and) / bahoo (daughter-in-law)/ ke beech (between) / tu-tu-maiN-maiN (petty argument/quarrel) chaltee rahtee hai (goes on).