How can I insert my dildos deeply?

Have a nice collection of different dildos, which I also use regularly to fuck me in front of viewers in porn cinema, in parking lots, cruising areas, in front of cam and for creating videos and photos. I love to feel it deep inside of me.
Unfortunately I am currently getting a maximum of 25 cm in my hot asshole. but I have a nice big one (35 x 8.5 cm) and a horny fucking hand (sometimes two cucumbers at a time) that I would like to introduce completely.

Do you have any tips on how I can put them all in and get half my forearm into my hole while fisting.