Tampons??only appropriat answers plz!!?

how do u insert tampons with out a applicator cause i cant seem to get it in right it doesnt like to be comfortable. i managed to get comfortable with twice but none ever since and it kills when i remove them im not sure wat im doing wrong cause i know wat angle to put them in and where and all that stuff but it doesnt work. and positions or lubricants that i can use around the house that would help?? and is it ok to finger urself in the bath or shower or is letting water in bad?? help and advice on equipment but no toys cause im under 18 but over 13?? and any other advise on tampons and other things??