Chapter 120:8-9
The Counting of the Omer
8. The "sundik" (the person who holds the baby during a circumcision), the
"mohel" (person performing the circumcision), and the father of the baby
may cut their hair (and shave), [even] on the day before a bris
(circumcision) toward evening (1), shortly before they go to the synagogue
[for the afternoon serivce] (2).
9. [A couple] is permitted to become engaged (3) and even to hold a
special celebratory meal ("seudas mitzvah"), at any time during the days of
counting the Omer. Dancing, however, is prohibited.
FOOTNOTES:
(1) And, of course, on the day of the bris itself, which is considered like
a Yom Tov for these three individuals.
(2) If the circumcision will be held on Shabbos, one is permitted to take a
haircut or shave on Friday, even before midday.
(3) This is permitted because there is a fear that if one put off one's
engagement, someone else might propose in the interim (Mishna Berura 493:3).