The 19-year-old, who scored in the Titans' 52-10 win over Parramatta on Sunday, also discussed the adulation he received in Papua New Guinea last year, with the forward looming as a likely target for the PNG Chiefs.
Bai knows what it is like to be in demand, having spurned the chance to join the Storm over the off-season, where his father - Kumuls great Marcus - made his name.
Bai's father was critical of his son's decision to reject the Storm and the chance to hone his craft under Craig Bellamy.
Cooper conceded he was torn about leaving the Gold Coast, before re-committing to the Titans until the end of 2027.
"It definitely was the toughest decision of my life I've ever had to make," Bai said.
"I've never had to make any decisions like that before, to pick between two clubs like that.
"I've grown up on the Gold Coast, and obviously I've got relations down south.
"To be honest, it was the toughest decision I think I've had to make in my life, being so young and having grown up here ... having all my family and friends around this area and on the Gold Coast."
Bai said the environment created by rookie Titans coach Josh Hannay had swayed him into staying on a deal that expires the year before the Chiefs enter the NRL.
"If they end up coming out in 2028 … I don't really think of that right now," Bai said.
"I'm just thinking right now. If stuff happens later, it happens later, but I'm staying around now."
Bai got a taste of the kind of reception he would receive in PNG after playing for the Kumuls in internationals at the back end of last year.
His every touch of the ball was cheered louder than any other player, and Bai is likely to experience more of that later this year, with the teen forward expected to be in PNG's squad for the Rugby League World Cup.
"I absolutely love everyone over in PNG," Bai added.
"The support and love that I get from everyone over there is tremendous. I've never felt anything like it at all, to be honest.
"It (the reception) caught me off guard a lot, it really did.
"I thought it'd just be playing a basic footy game. The boys always said it goes off when we're in camp, and the fans are always really loud.
"I was like, 'Yeah, yeah, I'll just have to wait and see', (but) to actually experience it was next level. At some points, I couldn't even hear myself, it was just that loud."
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