With the correct movement, that could be the BSL sign for 'linguistics' but i'm not sure how appropriate that is to your cause, unless you were mentioning how BSL is a language with it's own grammar, in which case that might be right. My personal choices would perhaps be this one or this one, but I suppose it depends on what you're trying to convey. Hope that helps.
https://www.british-sign.co.uk/learn-online-british-sign-language-course/ ^ good place to start
^ good book to buy
I know a lot of vocabulary in BSL but working on grammar now, I would preferably like to go straight on to level 2. I work in a deaf school (who don't use BSL) and one of my colleagues is deaf and has agreed to let me sign with her so hopefully that will help me reach my goal.
I don't know if this helps but I did a mix of signing with my little one blending Makaton and BSL as alot of the bsl signs are just roo difficult for children. I have a standard bsl app which helps for more obscure signs but mostly used books in the beginning.
This one was great for early signs and then when he was reading with me I got this AR book, their app is also really nice for children as it shows other children signing.
As I was doing it to improve his communication I was flexible with how we used from bsl, makaton, and signalong. It has worked for us and our 23 month old uses over 20 signs and responds to more, albeit signs that are often tweaked to his own vernacular.
Hope this helps!
I think that might be Signs of a Sexual Nature: An Introduction to Some Sexual Signs Used in British Sign Language by Cheshire Society for the Deaf, which was then Cheshire Deaf Society, and is now Deafness Support Network. I couldn't find a PDF and they don't seem to be selling it on their site any more. It might be worth Googling it in a few months though. PDFs of old books pop up all the time.