Do either of them fetch? My 3 love doing that together...so bc Wy always fetched, Marcel jumped in when he was a baby, as did Pfeiffer.
I know socks aren't the best idea - but using a gym sock to get one to grab - and then try to put the other end by the other dog's mouth can be good to start them up - the sock is nice and soft, and easy to grab.
Squeaky toys always get all 3 excited here.
What about running and having them both chase you...and then you get down and the floor and 'wrestle' w/ them?
Another one is Marcel and Pf LOVE playing hand games on our bed; as in, you put your hand under the sheet and move around really fast and they go after it...sometimes they then end up wrestling.
It will happen
!