my baby is exactly like that. they say na mas pasaway ang secondborn at bunso. also because with the panganay, you pay more attention so you can easily correct behaviour. for us, what works is talking. whenever my child is naughty. i talk to her ng eye level and tell her na what she is doing is wrong. also i offer alternatives like if she wants to watch but she's had enough screen time, i offer her toys. older siblings can also help by showing younger sibs how things are done or by being behaved also. you can also read this article: https://ph.theasianparent.com/discipline-without-hurting
Candice Venturanza