Thanks for the input, Lon Dubh and Saoirse.
Each answer brings to mind new questions. Would the following work? :
Tabhair barróigín do do mháthair. "Give your mother a hug."
Tabhair barróigín do Mhamaí. "Give Mummy a hug." (CO)
Tabhair barróigín do Mhama/Mhaime/Mhaimín. "Give Mummy a hug." (GC)
Tabhair barróigín do do sheanmháthair. "Give your grandmother a hug."
Tabhair barróigín do Mhamó. "Give Grandma a hug." (CO)
Tabhair barróigín do Mhaimeo. "Give Grandma a hug." (GC)
Tugaigí póigín dhom, a leanaí "Give (pl) me a kiss, children." (CO)
Tiúraigí póigín dhom, a leanaí "Give (pl) me a kiss, children." (GC)
For plural orders, the plural form of the imperative is used,
dhom goes to the end and
póigín/barróigín is in the singular, since it's asking for one per child (though you could also use the plural to ask for more than one from each person.) Nach ea?