Siman 558 – No eating of meat on Motzay Tisha B’Av

וChelek 6

113. Near evening of Tisha B’Av the fire caught onto the heichal and continued burning until sunset of the 10th of Av. Therefore the minhag is to extend the mourning until midday of the tenth. This includes:
     1. No eating meat and drinking wine.
     2. No musical instruments.
     3. No tashmish hamitta (unless it is mikva night or going/coming from a trip)
     4. No bathing.
     5. No haircuts.
     6. No laundry. (SHA – Rama – MB 2, 3)

114. If a seudas mitzvah is held this night everyone invited can eat meat, even non-relatives. (MB 2)

115. The seuda that the families make on the night before a wedding is not considered a seudas mitzva. Only the chosson and kalla and their parents are allowed to eat meat. (MB 2)

116. If Motzay Tisha B’Av is thursday night you are allowed to bathe, haircut, and do laundry for the honour of Shabbos. (MB 3)

117. When Tisha B’Av is pushed off until Sunday, you can already take a haircut on Sunday night since it is already the 11th of Av. Only eating meat and drinking wine should not be done. Wait until Monday morning. (Rama – MB 4)

118. It is considered an honour for the Bris Mila for the mohel to take a haircut beforehand. (ShaT4)