He wasn't intentionally being a pain in the ass, he was just used to being in charge. Since the party wasn't a surprise, the day before and the morning of had been full of 'helpful' advice, suggestions, and, of course, the commentary. As annoying as it was the tone had all been friendly and Tony had the interest of the guests enjoying themselves in mind.

After being told for the dozenth time the ladies and Gladio had the party prep in hand, he paced in the small manager's office fidgeting with this and that. That lasted about four and a half minutes before he thought of something else to check on. He was in the kitchen, checking on the food prep before it even crossed his mind he was supposed to be staying out of this.

"The anak might be good marinated in the stout," he remarked to whoever happened to be nearby.

Please get him out of here.

The gift [For Gladio]

Tony stood slack jawed a few steps inside the bar staring at what was on the stage. He looked at Gladio next to him confused and then back at the instrument. "How.." This was clearly what had made his partner so eager to get to the bar so early today but when had he had time to haul that in and where had he gotten it? More importantly, how had he known??

He opened his mouth again to attempt to say something, but couldn't settle on anything. He couldn't even decide if he should kiss Gladio or go check out the piano first!

Partying!

Dressed to the nines, Tony wore a black, real Italian silk tuxedo, a sleek black tie, and pristine black oxfords. He appeared even more comfortable in this snazzy suit than most people did in jeans and a t-shirt (which he'd been wearing often here too).

He flitted around the room like the social butterfly he was engaging in conversation, dancing with people, offering samples of one of his signature cocktails- the Iron Man-icane or Starktini in particular- while always having one he was sipping on. If anyone even sort of hinted they might want to, he'd readily offer a tour and show them the brewery.

He was shocked to see the number of cakes and could be seen taking breaks to sample the treats his friends had made for him. He was nothing but smiles and compliments- particularly toward Gladio for obvious reasons.

Music Fun! (Bonus! Tony getting embarrassed!!) OTA

i. In middle of the party, while Tony was busy talking and not paying attention to the music, a certain song begins to play. He froze and his face visibly paled as a familiar, not normally husky voice sang out. With wide eyes and slack jaw, Tony stood mortified as, you guessed it, everyone gets to hear his own voice sing Man Like Me with the piano accompaniment. He was going to murder Gladio...

At least it wasn't 'Baby Shark'.

ii. Since he'd already been 'exposed', Tony made sure the karaoke got started not too long after Gladio's stunt. Besides, he was pretty drunk at this point! He starts off the night with 'You Shook Me All Night Long' by AC/DC and then adds 'It's My Life' by Bon Jovi and a solo version of Every Breath You Take at later points.

Join in or bug him after a song!

Not really an option, but it's visible so.. There might have been more karaoke songs, but by the end of the night, he's too busy making out with a drunk Gladio in one of the corner booths. (I.e. Don't try and wait until the end of the night to talk to Tony and Gladio!)