When I was an infant, baby swings and bounces had an a-frame structure they hung from, similar to this patio swing:
Just build something similar from a few bits of lumber. You'll need four 2x3 studs to make one roughly 4 feet high and 2 feet wide.

Just build something similar from a few bits of lumber. You'll need four 2x3 studs to make one roughly 4 feet high and 2 feet wide.