Anal Depth Training

Would love to hear thoughts and suggestions to go deeper hitting a brick wall about 10-12 inches in .
Using a 1 1/4 er so 18 inch double dildo , and longer snakes but just cant seem to get past the 12 inch mark.
Pushing past the inner "Ring" pretty easy then about another 4-5 inches then full stop. Coming out clean so I dont think it a cleaning out issue. Anyway I appreciate any input!!