Step daughters/Asexual/Shower Sandra

"Well I think Masha is more than old enough to shower by herself and I understand how it could be troubling for such a young lady to have a adult male there while she showers so why don't I help little Sandra here first and then let Masha have a shower?" you say
Maria reluctantly agrees because that's a wasteful of both hot water and time but Masha greatly appreciates your unexpected support.

To not waste time you follow Sandra in the bathroom where she starts to undress. You turn on the hot water and turn back to see Sandra now fully naked.

"What a cute little girl you are" you say with a warm voice and before you can think, you pet her hair and face and tease her tit with two fingers.
Sandra smiles of all the attention she suddenly has but escapes you to go in the bath tub.

Then you start rubbing soap all over her soft body, tickling her on her tits, having her laugh when you rub her belly.
You skip her private for the time being and rub soap on her feet, legs and up her inner thighs.
"It is very important to clean your private parts very well, you know that" you ask her.
"Yes I know" she said in a bored voice as if it is usually a chore.

Here you are especially thorough, going slowly under her legs, rubbing very lightly at first and warming her up.
Sandra says "Hey, that tickles" and you can see her body moving like if you were tickling her but her eyes are starting to have a slightly different glow.
You keep doing it and eventually you see her close her eyes and start breathing faster and deeper while she gets relaxed.

Time is passing and you hear Mara say: "Breakfast almost ready, Masha needs to shower". You reluctantly remove your finger and says "Time to go little girl!".
Sandra, disappointed: "Oh already"

• You take Sandra off the tub and help her dry herself in her room