As an OG member of the MegaRod gang, gladly.
Rodimus is the more open of the two. The inhibitions that Megatron has about showing vulnerability aren't there in Rodimus. He doesn't silence or stifle his noises. He doesn't need to. Megatron, however, is still learning how to let himself be vulnerable.
It's a work in progress.
Which one is heavy on aftercare?
It's absolutely Megatron.
Despite them being pretty close to the same age, they've lived two completely different lifetimes. Megatron, through trial and error, has figured out how to finally control his own violence. He's so used to destroying things, not fixing them. Not cherishing them. Not caring for them. The trust the little Prime has in him is humbling.
Roddy is also incredibly bad at taking care of himself, both physically and emotionally. He's used to being used and thrown away, not something you keep. Not something you cherish. Megatron changes that for them both. It takes Roddy a long while to get used to believing that he's deserving of care, and proves to Megatron that something or one that he touches can flourish instead of wither.
Their love is not a fast thing, wounded and limping, but it is there despite it all.
Which one suggests using toys?
Roddy would already have a few, but Megatron would get him out and into trying things he wouldn't have thought of before. Turns out your ex-murderer is into some kinky shit.
Rodimus enjoys it.
Which one suggests recording?
Rodimus would, but Megatron would be the one who shoots it down. There'd be an argument, maybe a small fight- but they'd come back together. There'd be a compromise; no outside cameras, internal recordings only. In the bad universe, it would be the only thing Rodimus has left of his partner after the execution.
Which one gets shy asking for what they want?
Neither. They're both blunt as hell, and that part of their life has NO issues with miscommunication.
It's the whole "using words to communicate" thing they have issues with.
Which one is more likely to initiate morning sex?
Oh, they both would- but Rodimus would be the culprit for the one doing it the most often. Not that Megatron is against it, not in the slightest. He might grumble about being woken up before his normal time, but with a lap of squirmy speedster?
It's not the worst way to start your day.
Which one likes to use music to set the mood?
Megatron's last few lifetimes haven't exactly allowed him to figure out what sorts of music he prefers over others. It had usually been just whatever Soundwave plays at any given time.
Or the Miner's Rant that had been all the rage back on Messatine.
Rodimus is the one who introduces him to a wider selection, including music from Earth. Megatron is charmed despite himself and picks up some new selections.
Which one prefers handcuffs and which one prefers rope?
Megatron absolutely prefers the rope. Handcuffs are also okay, but he likes to tie up Rodimus snug and pretty. He'll hang him from that rope and just admire.
Rodimus looks so good like this; he can't help himself.
Which one prefers slow and sensual, and which prefers it rough?
Rodimus prefers rough, Megatron both. Rodimus hasn't had the best experiences in the world of interface. Most of his previous liaisons had been simple quickies here and there in between firefights. Megatron eventually gets him to slow down and enjoy the ride. It sorta rocks the speedster's world.
Not that he'd admit it, verbally.
Which one loves sneaking off at events for a spicy moment?
Rodimus, and he manages to rope Megatron into it- despite his better judgement.
Time.
Which one secretly keeps a list of things to try that the other finds by accident?
Megatron keeps the list, and Rodimus finds it. The issue is that Megatron writes in a completely different variation of Cybex than Rodimus is used to. It happens when you have language drift between the two factions.
Megatron reads it to him, regardless.