I'm apologizing because I made an accident and blew my cover instead of watching the whole way.
You can complete that quest by literally going to Marisa's house and visiting her room even though she's out.
The game will treat it as like she's still there and complete it too.
I find that immersion-breaking but funny nonetheless.
Reimu did say you could leave it at her doorstep. Last time I had that request was in my main save while getting Reimu to lover, but Marisa wasn't in the room when it popped up, she was in her room at Forest of Magic.
At SS intimacy/lust, just saying hello in the morning is likely to get you pushed down. Or at least that was how it was with Yuuka. And a simple skinship shoots up sexual frustration like 30%. And this wasn't even incompetent mode. Why yes, she immediaely got pregnant after giving birth, why do you ask?
They're very enthusiastic about it too for some reasons, doing surprise inspections and the like.
Haven't noticed this at SS alone and all mine are at EX, only when there's pink wind or they have at least 40% frustration and that's just them pushing me down, them asking to go somewhere private tends to happen at higher frustration for me, around 50% or more. I've noticed embrace is the go to for most characters to get that frustration up, but it also risks getting them mad at you. There wasn't a single time in my recent Reimu/Marisa run that embrace didn't get me at least one anger and it did make Marisa mad at me once, which I very quickly just lusted out of her (made her frustration shoot up, she pushed me down, I took the lead with my own push down, and I made her get off until she had no energy left), instantly not mad anymore when she was awake again.
I think it might be character specific weighting on how likely they are under given conditions. Yuuka, for example, seems to be an easier one to get her to do it.
Don't even get me started about Sakuya, she was inspecting me every turn by the time she started actively giving me, and specifically me, dirty looks when TSP things happened to her. Not sure it did much that she kept finding the exact same pair of her own panties on me a thousand times in a row on the same day before I went back and added them to my collection, it may not count toward getting her to do things to you without being a new pair, but I wouldn't know as I don't know what to look for to tell when she is doing things to me. I'm at the point where she talks about punishing me later and she opens push downs with a line about punishing me, but nothing happens with TSP, so I don't think that's it.