I mean, it'd be sad and annoying to get NTR'd by a seedy old man, but it does mean she'd be more open to night activities after the gate is down, right? right??
Saki tried to shorten "(a guy who was) planting seeds" which was "種を植え付ける(おじいさん)" so she said said ”種付け" which would translate to "a mating old man" ; to fit the seed analogy it was changed to seedy. I will add a TN later.