No it is not legal to have any contact with the goalkeeper.
Sexual contact is the touching or coming into contact with the penis, vagina or anus. This can be through touching yourself or someone else, or them touching you is considered sexual contact. While it technically refers to more than "touch" - e.g. it refers to contact as say a penis in contact with a vagina or anus, not so much as a finger touching a penis, etc.
Transferring charge by touching is charging by CONTACT
Sure. You can even contact AIDS from it.
That is the correct spelling of "contact" (touching, or to communicate with someone).