Probably, Oyashio is just too happy and tried to answer the welcoming (and manzai combi invitation) by giving tsukkomi. But her being blushingly embarrassed like that made things awkward
Oyashio's embarrassed at the idea of doing a tsukkomi, but went through with it anyways because her sister and squadmate put her on the spot.
This is embarrassing to even watch!Oyahh!Oyashio has arrived.What'chu talkin'about...!This girl is Oya-chan.We're makin' us here a Manzai Duo, yessir!And this is a congratulatory spring onion!POF!
Puchi 849 Blushing Comeback
And this here's Kuroshio and Kuro-chan!
Nice to meet ya'll!W-W-W-W..