It's not a bad feeling to have him stick his tongue really far in, but it's not the best thing he can do down there with it
I like to push my tongue deep inside the vagina, tease the clit, pulling the lips as far back as possible to ensure the clit is poking up. Also focus on the skin between the vagina and anus and of course the anus itself, i think most people love that sensation of a tongue rooting around the anal ring, getting in as deep as possible.
I can say from experience that boy or girl it doesn't really matter. For me it just feels unbearable when someone licks me down there. I literally can't stand it. Much rather have a hand on my pussy working away which is notably the only way I can get off. From what I can tell that makes me slightly weird among women but oh well.
My wife likes both - tongue penetration and clit licking/sucking. She usually orgasms instantly from having my finger on her g-spot and tongue play on her clit though. No reason not to do it all! Every girl is different though - it really depends on who you're with.
I wouldn't say weird, we all have our quirks Maybe you just haven't met the right person to feel comfortable enough to try it....
I always and up tearing my tongue webbings if I try and get my tongue deep so it's not something I really try and do. I put all my focus into what I can see. I really don't ever feel the intensity myself, but many girls I've been with really shake and shudder when I lick up about 2/3 from vagina to clit. Like the pee hole itself >.< maybe my tongue is shaped to feel good there.
I once licked a girls butt hole and she farted. Didn't put me off tho, guess its an occupational hazard...