Goldielocks,
One other thing...
Don't get in too big of a rush, hoping this activity will stop.
I probably won't, but, adjustments will be made as time
passes, and they get used to each other.
My situation was/is...
Just a few months ago, I brought a Female Puppy Becca into our family.
My Male Snickers was 2 years old, and is pretty hefty at 11 pounds
at that time. Sneakers and Becca are Brother/Sister, but a few
liters apart.
Becca is a very active girl, wants to play ALL the time, with anyone
who will participate. She and Snickers really get rough at times, with
him squashing her down with his paw, and holding his (much larger)
mouth around her neck, which I interpret as Doggy Manners 101.
They run, roll, bite each other (lightly) but there are a few "yelps"
from time to time. I do not intervene in this activity when they are
outside, but do limit their roughness when they are in the house. Becca
doesn't care where she plays.
I can see a genuine love being created between these two,
getting my Male a Female companion, was IMHO a VERY good
idea. They won't be having any Pups with each other, but the
fellowship between them, is something that I don't think a human
can provide regardless of how much we love and care for them.
It's just SO special.