The present participle is slipping (e.g. The cat is slipping off the window sill). Some verbs that end in a vowel+consonant will double the final consonant before adding -ING.
Slipped is the past participle of slip.
Being is the present participle. The past participle is been.
Getting is the present participle of get.
The present participle is doing.
slipped /slipped I slip, I slipped, I have slipped
Presenting is the present participle of present.
Presenting is the present participle of present.
The present participle is choosing.
The present participle is walking.
The present participle is cleaning.
The present participle is seeking.
The present participle of "understand" is "understanding."