I feel like it's important to the Aiichi dynamic that Ichigo fucking manhandles Aizen.
Ichigo enters a room already in a pissy mood? Aizen in a mood of his own pushes it a bit to see if he can and Ichigo stalks over and threads his fingers through his hair, then clenches at the back of his head and slams him down backwards onto the table, leaving his back arched in an uncomfortable way, and Aizen, thrilled, just grins and talks back when Ichigo speaks warning words in a low voice, looming over him in a way that's deliberately reminding Aizen of who won their one legit fight way back when.
Ichigo needs to move Aizen for some reason? Uses his superior speed to clotheslines him, slaps his palm to his face, wrenches him around like a ragdoll and then moves him where he wants him to be. Aizen recovers flawlessly every time, skin tingling where it's bruising and his lips twitching to not bear his teeth in a viciously pleased grin.
Just every once in a while Ichigo is super consentual ROUGH with Aizen because Aizen's the only one that can actually take the full force of his strength. The only one an accidental slip of his reiatsu won't blister and burn and bleed or kill. Because Aizen likes it. No one else touches him ever and variety is nice, and also he likes having the privilege of being the only one that Ichigo can or will be so uncareful with.