well there are plenty of sicko 20 year olds
( congratz on having the girl of your dreams
)
indeed your other sister might engage in that stuff even in a more zealous manner, make sure she isnt already
does she what her sis does? on the address you could indeed make a point about endangering the whole of the family
does yr sis have real life friends
? mebbe she just feels the ppl on net listen more carefully to what she has to say, or that they are more trustworthy ecoz they cant tell stuff to ppl in her immediate environment.