Yeah, a parent having the birds-and-bees talk with their adolescent kid is perfectly okay and one of a parent's many responsibilities. But getting all involved and showing their kids masturbation techniques and buying them anal beads, french ticklers, vibrators, strap-ons, etc. is overstepping parental boundaries by a pretty fucking large margin. There's no way that can be good for a child's mental well-being to have their parents getting all sexually personal.