The other translation is MTL.
"そのうちまた…そういう機会もあるかなあ……"
Or
"Sonōchi mata… sōiu kikai mo aru ka nā……"
It's vague.
"sōiu kikai" Isn't necessarily a reference to a past event. It can also be a reference to a future hypothetical scenario..
Nothing in her dictation eliminates either possibility.
You have to interpret it yourself..
In the final page of the chapter, she becomes
super flustered by the idea of buying it for his sake..
Which led me to believe her intentions weren't sex.
Remember how she was supposed to wear a swimsuit in the hot spring, and it broke?
She's probably thinking about buying something to replace it for the next time, "That" happens.
"That" is up to reader and translator interpretation. Could be another hot spring visit?
I translated how I understood it.
If you're worried about confirmation of them fucking, that becomes
even more obvious in future chapters.