@Randomizer
There might be a correlation with that, but the usual cause is depression
Depressed -> can't feel anything
Depressed -> will indulge with vices to cope with depression
Depressed -> will probably masturbate more often to cope with depression
@Steallet
Yamada cried due to being overwhelmed by both anxiety and guilt. You know, kids being kids.
She was having the time of her life, paying attention to nothing else but Ichikawa. This partly caused them to get separated from the group.
While she never says it (only internal monologue we will ever hear is from Ichikawa), she does feel responsible, considering that she waited for him outside and supposedly had every chance to tell everyone else to wait.